The big gotcha is what one understands under the word "use". If I want to USE it as a basis for my business where I sell routers with the GPL software, there are some tiny restrictions regarding that, as Linksys learned [0].

[0] https://en.wikipedia.org/wiki/OpenWrt (see History section)

That’s correct. You can’t take freedoms away from your downstream users. As I said before, violating a free software license usually means you are stealing from your users, negating them rights they ought to be given.

Distribution is a subset of use

That’s one semantic interpretation of “use”, but not the only or the obvious one.

For most physical objects and concepts, distribution isn’t a subset of use. e.g. the post office. You can be a user, but you have no ability to distribute the post office - because that’s not a thing that is possible or makes sense. In that case distribution is not a subset of use. Other examples: most saas, e.g. gmail. Good luck distributing gmail.