It's also a gross overreaction to shut down Parler because the vast majority of people using Parler or supporting Trump did not participate in the riot. Tens of thousands were in DC that day for various rallies and protests, and thousands stayed outside the barricades at the capitol. A few hundred went past them as protesters (rioters?), but committed no additional crimes beyond trespassing, which is the same as past incidents at the capitol like the riots at Brett Kavanaugh hearings (https://thehill.com/homenews/senate/405500-212-protesters-to...). Ultimately only 10 were associated with the Oath Keepers (https://www.nytimes.com/interactive/2021/01/29/us/oath-keepe...).
And on the balance, Parler had 20 million users (https://en.wikipedia.org/wiki/Parler) and Trump had north of 70 million supporters. It's not justifiable to stop all those people from having a voice. How was it at all justifiable for AOC to demand Parler be shutdown, for tech companies to immediately fall in line by banning the app, and for other companies to also participate in a seemingly coordinated deplatforming effort? It's also chilling to consider that a sitting legislator can call for the shutdown of the speech of private citizens - that amounts to the government coercing bans of speech from private organizations, and is a first amendment violation.
Either way, here we are, in a world where people depend on their mobile phones as utilities, but are serviced by companies that are not regulated as public utilities. They need to either stop being gatekeepers, and act neutrally, or they need to be regulated to enforce that requirement. After all, they are effectively immune to competition.