Sites like Parler might have started off with moderate conservatives and good "free speech" protections, but the more they grow the more they'll attract the dangerous let's go storm the US Capitol types.
This is my thought exactly.
I think it goes without saying that the overwhelming majority of people are pro free speech, however with that comes the fact that you have to deal with extremists. I can't imagine any normal person saying that the likes of hate preachers such as Anjem Choudary shouldn't have been locked up because it is a violation of his freedom of speech.
Society in general has progressed to a point where there is a rough baseline of what is acceptable and what is not; it varies from country to country but generally speaking isn't wildly different. When people deviate from these norms in the past, it was never a massive issue because in a room full of enough people their frankly ludicrous views would be shut down in an instant. Today things are different, we live in a world of social media where ideas spread like wildfire, for better or worse.
Anybody who has ever engaged with any kind of extremist/fringe views will know that they operate on misinformation/the distortion of truth. The problem that arises is that to have an honest debate with someone who doesn't 1. believe in objective reality and 2. is able to spread their word faster than any sane person can rebuke it is a recipe for disaster.
It takes an order of magnitude more time and effort to rebuke bullshit than it does to spread it. This is an undeniable fact.
This is where policing and fact checking come in. Sometimes it can be, and is heavy handed. Other times it isn't heavy handed enough. Who draws the line? We all do, collectively as a society.
 I am habitually against facebooks move into sharing data with whatsapp, etc; however it would be hypocritical of me to leave facebook based on that as they already have all my info there. There's nothing I use whatsapp for other than group chats and spamming friends with shit memes.
I genuinely think a bigger stance needs to be taken against governments overreach into individuals data rather than private corporations. Theresa May's snoopers charter/the five eyes agreement for example is totally unacceptable in my opinion. I'd consider voting for people who would extricate us from those.,
My two cents.