Really an issue is Social Media being used for Official Statements (tm). Like, my random ramblings or tweets about my cat are not equivalent to an elected official declaring martial law, but if they're using Twitter as their place to do that then both of them are the same. So you either have to mandate all businesses treat all people as special precious babies whose opinions matter deeply and must be shared at all costs and the mean businesses have no right to kick them off their lawn for rambling about the black people stealing their hair boo hoo, or declare politicians as super special internet citizens with enforced online political immunity.
If you can't tell, neither of those are acceptable options to me. The former is something websites should be able free to police on their own, the latter basically breaks the idea of a free internet.
So instead, why not legislate that Official State Channels are the only means of conveying Official State Information, and any other business is just a rebroadcaster: Not allowed to maliciously alter the content being broadcast, only independently audited unbiased samples, but not required to broadcast it? Anything not from official(tm) state-controlled sources is to be treated as no different from anybody elses the ramblings: Potentially useful for the public to know about, but not something anybody has an obligation to carry.