Gaga Episode

So I'm watching the simpsons seasons backwards (on 22 now) and I wasnt looking forward to the gaga episode because I've seen how many people hated it. Just watched it today and I dont get why? Seen so many people be nasty about Lisa and i find it really odd? Don't get me wrong, she wasn't nice to gaga .. but she's an 8 year old girl who was just voted least popular in her year and was publicly humiliated by her brother?? Confused why so many people were angry at her for her behaviour, because I've seen some really nasty comments.

Tbf, the mean comments were on instagram so maybe the opinion on the episode is different here