"no, I won't provide a source for my claim, because my source is not good/non-existent"
FTFY
provide the reason you don't like those studies
They didn't say they don't "like" the studies though, in fact they actively said they were interested in seeing them. What's the point of asking someone to explain why they don't like something that they haven't even seen yet. Sure they could go find some random related studies and then critique those but that seems pretty pointless.
Edit: since I'm whining about lack of sources, I should probably give some myself
Here's a paper investigating the correlation (or more specifically, lack of correlation) between social media usage and mental health outcomes for young adults: