The government doesn’t need to do it, since it has been replaced on a lot of matter by corporations. Never in history companies held that much power on people’s life. Arguing for deplatforming because "muh private" is missing the fact democracy emerged to limit the most powerful entity at the time (government). Now that companies are the most powerful element of society, their power needs to be limited as well.

They're not the most powerful. They're just the most popular. There is a difference. They have ZERO control over your life. I know because I don't use any of them and I live just fine.

Really? I find it hard to believe you don’t use anything for a big company. No credit/debit card, no bank account, no car, no electricity, no smartphone? To be clear I wasn’t just speaking of a few US tech companies but enterprises like the fortune 500 or the CAC40 which have a enormous power on people’s life.

This comic is very relevant to your point:

http://stonetoss.com/comic/build-big/

Don't complain when it starts happening.

Makes sense. But mail order still exists. At least we can still say what we want to promote change without fear of arrest from our government. If the argument is just. I'm sure it will do well on it's own. Democracy isn't perfect but it's better than the alternatives.