The difference with those was: the alternatives were not easy to reach. There was only one phone provider supplying your home. There were few (if any) competing gas stations in any area.
You want a competitor to Facebook? http://MeWe.com - there you go, one click right there and you’re on another service.
You want a competitor to Twitter? http://Gab.AI - there you go, one click right there and you’re on another service.
You want to BE a competitor to either? https://AWS.Amazon.com - everything you need to build The Next Big Thing™ at a modest & fair price.
Nothing stands in your way. FB isn’t blocking anyone from use (except for whom they’ve stupidly kicked off).
Customers _choose_ to use Facebook, Twitter, etc. That so many do doesn’t make either a monopoly.
I was "suspended" twice, for the same thread. I had the audacity to refer to the gender confused as trannies. This must have triggered one or more people. My response was to stay off of Facebook for two days for every one day I was barred. After a few days I started getting e-mails from Facebook wondering why I wasn't logging back in.
And customers did not have to use microsoft’s Browser when it was added to their windows operating system. There were competitors like Netscape navigator......yet since they were the 800 pound gorilla and had a dominant market position, regulators put all kinds of restrictions on them and even required them to decouple their web browser until other major competitors like google and Firefox came along and grabbed a big chunk of the market Microsoft was trying to dominate.
Facebook and YouTube and Twitter are the 800 pound gorillas in their markets. Antitrust action against them - particularly if they’re being arbitrarily restrictive toward free speech is fully justified.
The competitors you list are not competitors they are wannabe alternatives.