I also don't understand what tech companies are preventing from being discussed? The issue with Parler is they weren't moderating to delete violence inciting commentary - if Parler had done an adequate job of that then the app would still be accessible on those app stores.
More government control leads us more towards a CCP state, whereas the freedom of businesses to be relatively sovereign is a failsafe against potential tyranny - and where people are "voting" for the companies they support the governance of by buying their products, services - allowing them to earn revenues/profit to continue existing; yes, there needs to be even more competition to prevent oligopoly behaviour, and there is policy possible to help with that - especially what's needed is good data and network portability laws so people's online life is easily mobile, as well I believe there needs to be a mechanism that extracts more value from businesses that gain benefit from economies of scale for various reasons.
Just as a reminder, the deplatformed population was pushing (and the platform was enabling) fighting words - https://en.wikipedia.org/wiki/Fighting_words
By the way, the "fighting words" decision(like the other oft-favored "fire in a crowded theater" quote) are great ironic examples of what kinds of speech you are looking to suppress - a Jehova's Witness swearing at police, and a protestor against the draft in WWI. You don't need to be imaginative to see how these "reasonable limits to free speech" will be used negatively, you only need to look at what they were created for.
Had Wednesday not happened, there would be no ability to consider the language in scope as such.
Vague threats were made, impressions were that there was no telling whether or not they were serious, and then the insurrection happened.
If we can't discuss and address it and other sensitive things like it that are evil and are approved-speech by tech then we're doomed as a society, and I'd say we're no better than actual racists, oppressors and slavers from days past.
Moves like this by tech companies only makes it worse and more difficult to discuss this.
I don't know where I'm going with this, but these recent steps taken by tech are incredibly disturbing.