First of all I tell everyone who asks why I ask this question is about the use of licenses in different free and open source operating systems such as BSDs (OpenBSD, FreeBSD and NetBSD are my favorite operating systems if you ask, which is also another reason to ask these types of questions). In my opinion, copyleft is not necessary because if I used a permissive license (the most permissive that exists) obviously I know that someone can fork my software and convert it into proprietary software, that the changes are not released, that maybe just look my code to see what can improve your program or whatever and well he does not have to give me anything back and I do not care if he does, of course there will also be those who want to collaborate with me to improve my software but finally using a permissive license not I find no problem in someone doing what they want with my code because it does not affect me, in fact I am in favor of them doing so because it does not affect me at all, also considered that permissive licenses have less problems (or none) of incompatibility with others Free software licenses, something that does not happen with the GPL, also personally for me the only licenses that respect both users and developers alike (or anyone related to the development of such software). In summary for me, copyleft tries to solve a problem that does not exist and thus generate incompatibility between some licenses due to its absurd and ridiculous terms and conditions, all because it is against proprietary software and because I support free software but GNU. / FSF and its disgusting Copyleft is something I don't want to have anything to do with, well I don't like copyright either, it's disgusting (no matter how permissive) that's why I'd rather use CC0.
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