Steemit is censorship resistant since no one can delete or remove comments or posts. They can only be hidden on steemit.com and there are other sites that don't hide them. Flagging may remove rewards and lower reputations but it can't stop them from posting and commenting if they choose to.
There's a lot of intolerance towards other peoples viewpoints in certain tags & topics of discussion. In an ideal world everyone would act like adults and respect each other but that doesn't always happen and it tends to lead to flag wars.
Flat-earthers and the scientific community are two that frequently clash leaving a lot of fallout with flags and low to negative reputations. Mostly because they persist on commenting on blog posts after they have been asked to provide scientific reasons for their beliefs or stop commenting. A lot of users don't use the "mute" button either as they want to make sure the commenters aren't earning rewards they see as undeserved.
"flag wars", excatly what I meant.
Alright, still getting familiar with how steem works =P.