This is precisely the wrong way to tackle it though. We cannot ever allow government to control what can or cannot be said, outside narrow limits such as incitement to violence. Making the case for the truth will just have to be done the hard way.
Fortunately it looks like this is only 2 congresscritters, not “House Democrats” generally. There are at least a handful of utter wing nuts on both party benches so last put this in perspective.
The main problem with social media services is algorithms that drive engagement by turning people’s feeds into an ever more extreme echo chamber. Whether it’s lefties being zombified into SJW snowflakes deplatforming people on campuses, or Qannnon turning people into alt right political flat earthers. That’s what they need to address, picking and choosing opinions to block is a fig leaf move that’s more likely to backfire than improve anything. It’s a hard problem though. What do we do about these engagement algorithms? I’ve no clue.