>I think you're being disingenuous, I don't use my lawn to distribute other people's apps/signs, it's not its purpose, and I don't advertise it as such.

That's irrelevant, at least under US law. If your daughter sells lemonade on that lawn, is it more of a platform? Can I then post signs all over your lawn about the dangers of lemonade or citrus?

Of course not. Because on your private property, you exercise your own free speech rights by allowing/disallowing what ever you choose.

Why should it be any different on F-Droid's private property? Do the people who own F-Droid have less free speech rights than you do? If you believe so, please explain your reasoning, as I don't see the difference.