You're not wrong, but that is why it is important to teach these life skills to children.
If she placed that much value in what malicious strangers said, then I feel that reflects on the parents failing to prepare her for life.
This is true, I can't argue with it. But recently there's been a bunch of stories about increased suicide rates and kids/social media. Yes, parents have a responsibility here, the major one, and maybe it's time more exercised that and steered their kids away from it entirely.
All the generations before them survived without posting selfies, I'm sure the current one could survive without it too. Can't tell you how gross I find mother daughter duck face selfies.
The trolls can drive many over the edge, anyone who's been around has seen that. Me, I don't lose any sleep over such irrelevant things, but a young teen, I could easily see it.