I think it's actually more common for laws to exist because people wanted them despite enforcement being impossible than because people wanted them and could have them enforced.
Consider things like the Jewish law that a child who disobeys his parents must be stoned to death.
Is this a typical "more common" example of law though, or some curiosity from antiquity?
How many modern laws are wanted "despite enforcement being impossible"? (Which as per your example, doesn't even mean "enforcement being impossible" but rather "enforcement being undesirable" or something). We have some laws that we can't enforce in the sense of there's no easy way to practically check if somebody broken it (e.g. pirating some software). But most laws we can and do enforce them if the perpetrator is caught.
There are quite a few laws in the US that give special legal privileges to some construction such as "the top two political parties" or similar. For example, specifying that a committee's membership be composed of 1/3 one of the top two parties, 1/3 the other of the top two parties, and 1/3 unaffiliated. Or 1/2 one of the top two parties and 1/2 the other one.
You're absolutely correct that this is completely unreasonable, but it's also common as dirt.
At best, it's a matter of judgement of what's desired socially.
Actually that's exactly how monopoly law works, checking dominance in a market.
It's also not different from the subtle laws (even in US) for determining religion or cult.
>Twitter might be popular today, next year it could be something else.
That's not a problem at all, as a law could e.g. cover all social media companies "above a certain user threshold".
>And how would you even define "social media" in a way that would pass Constitutional muster?
I don't really need to pass U.S Constitutional muster, as I'm speaking about E.U. That said, I'm pretty sure if US legislators wanted it, they could find a way. They have defined what's journalism, they could also define what's social media. Or they could extend the law to all media.
Laws don't exist because of this or that physical necessity. A physical necessity might encourage us to make a law, but in general laws exist because people (or at least, the legislative body) wanted them and can have them enforced. There's no physical necessity that says children should not work in factories, for example. They very well could in the 19th century (and well into the 20th, even in the USA). We just willed it as unacceptable and voted it into law.
So whether fairness doctrines where initially made because of limited time/space on tv, is neither here, nor there. A law could enforce it for any website that operates as a journalistic website, or is above a certain size, etc.
But even under the "law exists because of limited resource" model, the argument is flawed. Specifically:
>By contrast Internet bandwidth and sites are effectively infinite so there's no need to force access to any particular platform. Just use a different one, we have lots to choose from.
That's also neither here, nor there, as some platforms are more dominant than others.
The fact that politician X can get on Facebook, while Y cannot because FB doesn't let them, can already influence elections to the point of election fraud -- even if Y can still open a Tumblr or run their own webpage. It's where the eyeballs are that matters, and "viewer capture" is still a limited resource (that's the same thing that FB and co sell to advertisers: that they are the place where most people are).
And of course this setup (allowing X, disallowing Y candidate) can be leveraged as a mean of influence, from FB or from some country that controls FB for its foreign interests, or be sold as a service to the highest bidder "we advertise you, and disallow your opponent". The deal can be made under the table, if needs be.
Such a law is perfectly reasonable and doable, even if it explicitly regulates only a specific part of social media (say, the top-dogs of user engagement like FB, YT, Twitter and co, and not the long tail, e.g. some random blog or Diaspora).