I think you are conflating "the best data we have" with "sufficient data to prove something".

I agree with you that the best data we have is inconclusive. Which doesn't mean social media is totally safe. Also it doesn't mean it's totally dangerous.

It means there just isn't enough data to let science guide the decision. Science is very slow and very expensive.

So since I can't wait another century for their to finally be good science about social media, I have no choice but to go with my gut.

Which means, IMO: (1) regulation should be limited to what the general public's gut on average agrees with, since science won't be the neutral arbiter we want it to be for the foreseeable future. (2) I personally want to severely limit my kids access to social media because my gut says it's addictive and harmful. But I don't expect society as a whole to agree with me on that.