Maybe applying common carrier status is something that's more palatable, but classifying them as "public utilities" doesn't have to be the mechanism by which CC is applied.
Of course, one could bring a distinction between things that naturally grant a physical monopoly and things that don't, but I think one could make an argument that certain sites have effectively become the new public square and in doing so have a natural monopoly of our attention (or more pedantically a natural cartel).
There is also a natural monopoly of technology. If you have a patent for something, others can't use it unless you let them. Imagine if every major tech corporation aggressively pursued every possible patent claim against any companies trying to offer an alternate space for those banned from the mainstream, would the little company have any greater chance that a new electric company fighting against the entrenched players?
When access to it is required to be on an even playing field.
Hence internet, yes. Electricity, yes. Phone? Yup.
Facebook? Ehhhh
By the same measure, depending upon what you are trying to do, it will not be an even playing field if you are removed from Google, Facebook, Amazon, Twitter, etc.
Being banned from Facebook/Google/Amazon doesn't prevent you from using the free irs file option, or applying for your ID online, or helping your child with math homework you have no idea how to work on cause you grew up without access to schooling, or etc.
I'm more talking level playing field for your average American, not your average hackernews poster.
That still leaves plenty of room for the removal/censorship of violent videos, copyright-violating videos, and content with outright calls to violence. Honestly, I've seen a ridiculous amount of the above three examples on all platforms to come to the conclusion that it's both impossible to police such content properly, and that the attempts at classifying content with political speech under the same umbrella is just silencing/censorship rather than it just being a matter of consistency.
While I agree with you on Twitter, these two are less clear.
Google wields vast influence by being search provider, advertising provider, email provider and phone provider simultaneously. Google IS the panopticon for the average user.
Facebook is someone I can't avoid in quite a lot of situations. When government starts using Facebook to coordinate and contact (and it has), Facebook has become more than a mere company.