I think it las less to do with bad parenting, and more with what kind of weirdos and also oversensitive snowflakes the people involved are.
It sounds ridiculous, but look at it from our own experience with the "internet LGBT" people who we are talking about here. We are talking about people who can supposedly be driven to suicide by mean forum posts, and get PTSD from Twitter.
Of course an average teenager can bully them. Many people "bully" them without even trying, a mere open debate is enough to be considered bullying them.
And that's without even getting into the obvious fact that "LGBT parents", especially the kind who would complain to the media, almost certainly don't have children in a normal and healthy family environment and dynamic. These are probably post-divorce and if they do have a father, he's one of *those* kind of people you see on shock photos from pride parades, or at least Carlos Maza tier snowflake.