girl it's Taylor's team that do all that mess and they are doing it to protect her music and her art. Nothing they are doing is illegal or wrong. Sure it's annoying AF but it's not wrong.
Halsey garnered fame through Tumblr where she ran a One Direction blog in late 2012/early 2013. Her song about Haylor (Harry/Taylor) that was a parody of I Knew You Were Trouble. went viral, as well as her original music which was all based around the band. This caught the attention of labels, she got signed and now she's... She's Halsey. But yeah. The foundations of her career is writing songs that shade Taylor. Some things never change I guess.