First level itens are questions/objections that might come from the public. Second level are part of the possible answer.
* GPL/AGPL/FDL are too long and require huge license notices.
** These are the only licenses that:
*** Define what "source code"/"source files" is. **Most** (not all) of the other licenses (specially: CC BY, CC BY-SA) don't have such definition.
*** Specially in the case of the latest GPL (I have only read **this** entirely): Have provisions against digital handcuffs.
*** Specially in the case of the latest GPL: Have previsions against overpriced redistribution if the redistribution in binary/ready/object form is made **first and with a price/charge**, in which the redistribution of the source happens only when requested by the user and so the redistributor tries to charge once again (in this case, the GPL limits the second charge to the direct costs associated with a phisical redistribution, so the redistributor cannot put profit margin upon this charge). This doesn't apply if the redistribution happens in source form only, and also in some other scenarios described in the GPL.
* These licenses require that one inserts the license notices in every file.
** No, that's a recommendation, so that, if the whole project's source files happen to be downloaded by the user, and the user then takes just one single file out for use of his own reason, he can be quickly reminded of the license. This answer is similar to our reasoning for correctly licensing JavaScript, in that the web developer receives the README and LICENSE/COPYING files, and simply deletes them, or choses not inform users/visitors of the site about the license of the JavaScript and, most importantly, about where to find the complete and corresponding source code/files.
* Are functional data under the Peer Production License, a copyfarleft license, considered free/libre?
** No, because it restricts selling. The PPL can be used for non-functional data. The Telecomunist Manifest, that created the copyfarleft movement advises *against* using the PPL for functional data, and *considers* the GPL and related strong copyleft licenses as the best ones for functional works. See: <https://www.gnu.org/licenses/license-list.en.html#PPL>.
* Is ZFS free/libre software?
** Yes, it is. However, due to poor licensing choice from the copyright holders of the ZFS implementation for the Linux kernel, redistributors must-not redistribute ZFS in object/binary form, only in source form. See: <https://www.fsf.org/licensing/zfs-and-linux>.
* Is CC BY-SA a GPL equivalent for non-functional works?
** Not exactly. The closer equivalent is Free/Libre Art License, this is the license that the FSF recommends for non-functional data. See: <https://www.gnu.org/licenses/licenses.html.en#OtherWorks>.
Regarding your last questions: It all depends on your target-audience. If you know that they are willing to learn such things, do so. Note that according to The Principles of Community-Oriented GPL Enforcement published by FSF and Software Freedom Conservancy (<https://www.fsf.org/licensing/enforcement-principles>), this must be done in a collaborative way first, presenting suggestions, asking for the violators to help on solving the issue together with you, and perhaps even asking them to assign someone from their group as a "copyleft compliance manager" for that issue. There's a rescent discussion on libreplanet-discuss mailing list about GPL enforcement in China, in which someone suggested this "manager" assignment, see: <https://lists.gnu.org/archive/html/libreplanet-discuss/2016-06/msg00052.html>.
* GPL/AGPL/FDL are too long and require huge license notices.
** These are the only licenses that:
*** Define what "source code"/"source files" is. **Most** (not all) of the other licenses (specially: CC BY, CC BY-SA) don't have such definition.
*** Specially in the case of the latest GPL (I have only read **this** entirely): Have provisions against digital handcuffs.
*** Specially in the case of the latest GPL: Have previsions against overpriced redistribution if the redistribution in binary/ready/object form is made **first and with a price/charge**, in which the redistribution of the source happens only when requested by the user and so the redistributor tries to charge once again (in this case, the GPL limits the second charge to the direct costs associated with a phisical redistribution, so the redistributor cannot put profit margin upon this charge). This doesn't apply if the redistribution happens in source form only, and also in some other scenarios described in the GPL.
* These licenses require that one inserts the license notices in every file.
** No, that's a recommendation, so that, if the whole project's source files happen to be downloaded by the user, and the user then takes just one single file out for use of his own reason, he can be quickly reminded of the license. This answer is similar to our reasoning for correctly licensing JavaScript, in that the web developer receives the README and LICENSE/COPYING files, and simply deletes them, or choses not inform users/visitors of the site about the license of the JavaScript and, most importantly, about where to find the complete and corresponding source code/files.
* Are functional data under the Peer Production License, a copyfarleft license, considered free/libre?
** No, because it restricts selling. The PPL can be used for non-functional data. The Telecomunist Manifest, that created the copyfarleft movement advises *against* using the PPL for functional data, and *considers* the GPL and related strong copyleft licenses as the best ones for functional works. See: <https://www.gnu.org/licenses/license-list.en.html#PPL>.
* Is ZFS free/libre software?
** Yes, it is. However, due to poor licensing choice from the copyright holders of the ZFS implementation for the Linux kernel, redistributors must-not redistribute ZFS in object/binary form, only in source form. See: <https://www.fsf.org/licensing/zfs-and-linux>.
* Is CC BY-SA a GPL equivalent for non-functional works?
** Not exactly. The closer equivalent is Free/Libre Art License, this is the license that the FSF recommends for non-functional data. See: <https://www.gnu.org/licenses/licenses.html.en#OtherWorks>.
Regarding your last questions: It all depends on your target-audience. If you know that they are willing to learn such things, do so. Note that according to The Principles of Community-Oriented GPL Enforcement published by FSF and Software Freedom Conservancy (<https://www.fsf.org/licensing/enforcement-principles>), this must be done in a collaborative way first, presenting suggestions, asking for the violators to help on solving the issue together with you, and perhaps even asking them to assign someone from their group as a "copyleft compliance manager" for that issue. There's a rescent discussion on libreplanet-discuss mailing list about GPL enforcement in China, in which someone suggested this "manager" assignment, see: <https://lists.gnu.org/archive/html/libreplanet-discuss/2016-06/msg00052.html>.