People are such ass holes towards her. Tbfh it's usually the same folks who are like "omg i was bullied for my sexuality and now i have depression #noh8 #itgetsbetter" yet they attempt to invalidate Halsey's sexuality, mock her mental illness, encourage her to commit suicide on a daily basis (while knowing she suffers from the depression they claim to have) and try to erase her race because she doesn't fit into their perceptive of what an interracial woman should look like. And they're like "if she can't handle criticism she should leave twitter" but when she does they say she's a coward and start attacking her on other social media sites. All of this hate because they can't get over a few similarities to Lana (yet praises other tumbler-eque artists who are very similar to both artists)
And the Instagram thing, everyone shares things without credit. Though artists should be recognized for their work, we live in a world where things are shared over and over and over again and credit is sometimes lost. She didn't pretend that she made it, she just shared a damn picture then credited the artist. People will find any little thing to criticize her over.