Sure but that's mostly irrelevant in practice now. Gpl was notoriously unenforced so this aspect of "getting source code" almost never yielded to much in practice. FSF did a great job with limited resources it has but as code copyright is basically gone now and reverse engineering is so accessible we can actually empower real free software that is fully transparent and verifiable. If you imply that somehow we'll start regressing existing tools to proprietary software I don't see that at all.

@fruitcantfly @drmoose Just. Wrong. Clearly 'Linux boosted' is a worthless accolade.

That's not true at all. Like I said, copyleft relies completely on copyright. It was not at all created in opposition to copyright. It was created in opposition to proprietary (i.e., "unfree") software. Here, from the Wikipedia article on Copyleft (emphasis mine):

The concept of copyleft was described in Richard Stallman's GNU Manifesto in 1985, where he wrote:[6]

GNU is not in the public domain. Everyone will be permitted to modify and redistribute GNU, but no distributor will be allowed to restrict its further redistribution. That is to say, proprietary modifications will not be allowed. I want to make sure that all versions of GNU remain free.

This is impossible to do without copyright existing. Like I mentioned before, without copyright laws, companies can take any code they wish, with any license, and use it in their proprietary software without sharing their modifications.

Another reference directly from the FSF: "Copyleft is a tool that works within copyright law" (emphasis mine)