You're starting with dumb axioms. Free speech is obviously not a self consistent principle in the way that you're talking about it. Unregulated speech with no protection for fair apportionment of the channels of speech is very obviously not free. A silly example, do I have the right to speak exactly out of phase with you so that you can't be heard from some directions? Do I have a right to buy every local news station and have them all report the same thing? Both of these are me restricting your speech with my speech.

Paid advertising is not fundamentally different from these.