Actually it's the biggest deal since 1A applies to .. the government

The 1A applies to the government forcing people or companies to restrict their speech. Since Twitter has not alleged they were forced, that means they were asked and complied voluntarily- which means it doesn't matter if the person who asked was an elected official or not, from a 1A perspective.

Ah I see what you meant.

I guess people's argument then would be that the govt (or whatever) indirectly limited Twitter user's speech.

The First Amendment constrains only the government, so it is the biggest possible deal in this conversation.

If you are talking about the a more general ideal of "open and free speech" - which private companies are never legally required to uphold, but may choose to espouse anyway - then it's clearer to say that instead of conflating it with the First Amendment, which will just distract others from the points you're trying to make.