While I agree with your position that boycotting these platforms is a good thing, however, by boycotting these platforms for banning people that they do not want participating is playing into their hands.
Facebook / Google / Twitter each have a motivational interest in doing what they can to influence this upcoming US midterm elections. They are where the bulk of users are hanging out. As much as it is a good reprieve to participate on forums like Steem, minds, gab, etc... This is not where the battlefield is.
We are in an information war; the battlegrounds are these massive platforms. Where they are trying to implement the censorship. By boycotting and just leaving those platforms, we are allowing them to be taken in by the owners and manipulated to their benefit without any opposing voices.
You don't win a war with retreat.
Let's accept that premise (I strongly disagree for several reasons); that leaves 10's -100's of millions of people who are kept in those informational ghettos.
Those running the ghettos want to keep the people in them within them, and to do that they need to sequester them and keep them in their little echo chambers. This is an information war. These platforms are the war zone.
We never would have won WW2 if we said "well, Germany is nazi territory, we should just let them do what they want with it." FUCK NO!!! We sent people in to take it back over whatever the costs, and MILLIONS paid with their lives.
We are lucky, we get to engage in this war without the need for the blood and bullets, we get to launch memes and counter narratives with facts.
Yes, was given a choice : here's a platform where you are free to post about yourself, and share and find and meet lost friends and family...
Once the userbase is around a billion (probably counts bots), and the platform is pervasive, they are now acting like your phone company. A utility to connect people.
Also, people have built the value of the platform...
So, it's like if you helped build the telephone grid, then, once established they decide "ok, you are ONLY allowed to talk about the weather, or we will remove you from the platform you helped build."
BEST CASE, we are looking at monopoly practices that saw microsoft split up as a company.
Oh, and as a bonus, they get government money, which makes it government sanctioned censorship.
BTW - the analogy to WW2 does have a premise : That if our parents / grandparents (not sure your age) had had the attitude of cowardice that you are expressing, we would all be giving nazi salutes.
I'm not talking about ownership. I'm talking about treating this like a war.
Like it or not, WW4 is going on and it is for the hearts and minds of the people of the planet.
So, we can act like the jews and hope for escape, we can act like the french and give in, or we can act like the russians and show these fuckers who really runs the show.