As stated above, you can have hard rules like not posting explicit pictures or someone's real name and address. However, the ones that really should be banned do not break those easy rules to defend.
It can be argued to death if Trump's tweets instigated a riot. It can be argued to death that NJ Dan is annoying and abrasive and makes this place less enticing to visit. More or less Twitter didn't want Trump to use their platform to spread his lies. That is the reason behind him being banned, plain and simple. Just like McDonalds can ban me from going in there after I pee all over the counter, Twitter can ban someone for whatever reason they want.
None of this should surprise anyone with regards to how big companies do business. Wait until you hear about FTX and how they sent lobbyists to decrease regulations so they could steal more money.
For someone that wants less government, it sounds like you want more.