Why should a billion dollar corporation get to decide which opinions are acceptable and which views don't get a platform? I'm as far to the left as you can get

Why should a billion dollar corporation get to decide which opinions are acceptable and which views don't get a platform? I'm as far to the left as you can get. I used to support stricter moderation on social media platforms, but I'm putting my foot in my mouth now. In practice, these corporations are just as likely to censor leftist views as they are to censor right-wing views. Even people who study history and politics don't agree on definitions of racism, sexism, etc. There's a lot of nuance that a $10/hr contractor who sat through a one-day training on offensive content at Facebook won't understand. This type of censorship doesn't help progressives, it just lets corporations determine the window of acceptable discourse.