But if I want to use the public forum that has been created, I'm forced to agree to those ToS. Imagine for a second if those ToS included something like banning all people from the state of New York or it banned all socialist. The government, by picking a service with a ToS to host a public forum, is there by enforcing the ToS as a requirement to participate in the public forum. So why can the government enforce a ToS that wouldn't be allowed without the 'private company' loophole?

Now, twitter banning someone from all other parts of its service wouldn't be impacted. But banning someone from participating in the public forum should no longer be allowed unless done for a reason that the government would be allowed to use as well.