It may be hard to understand for some, but there are topics that make people highly uncomfortable. These people prefer an environment that 'protects' them from fringe ideas.
The issue is, the 'Overton Enforcement' doesn't work when a large minority (say, 30% of users) has ideas considered highly controversial to the majority of users. Most people actually do want to live in a bubble most of the time so being exposed to these opinions undermines their sanity.
A 100% free speech platform could work fairly well though if it was sophisticated enough to understand what a user does and doesn't want to see and then only occasionally expose them to controversial content. Kind of like TikTok's 'for you' page but with less censorship. Or, perhaps, let users control their exposure directly. Twitter doesn't have the technical capability to pull this off though so they are stuck with occasionally infuriating large minorities of users.