I fear that there is definitely something brewing in our online habits these days, and it may be significantly damaging to society.
The problem however, is that removing these groups will not inherently solve them. I would support removing of these extremists if i thought it would do good. It however, won't. It will further build the fire of self-victim identification and extremist views which fuel them.
We need another approach at solving this problem. Of which i think is two fold:
1. Groups (both the left and right) struggle to stand up against the undesirable extremists within.
2. Our ingestion of information is not filtered enough by our own brains. We consume freely, and largely due to extremists and bubbles we end up consuming garbage.
All of this said, i feel like attempts at dealing with Parler is vastly different than the "cancel culture" which attempted to rename the https://rubocop.org/ tool. One is a misguided answer to extremists - the other is an attempt at protecting hurt feelings over bad words. Very different.