Why does my ex's best friend stalk me online?

[Anonymous]

My ex cut me off months ago and her best friends defended her and I was seen as the crazy and clingy and cry baby ex.
I apologised for nothing a few months ago although she was the one that dumped me and it ended there.
But last week it all came back and I lashed out at her online because truth is she left me devastated.
She blocked me thereafter and her other bestfriend told me to stop being an asshole.
But her main Best Friend, who I fought with during the breakup stalks me online since the last week. Why is she doing this?
These guys don't care about me, they have their lives and really cool guy friends, I'm just a kid who does my art and post dogd.. Why do they want to come again and again to see what I'm doing?
Like seriously I try not to bother with it, but why do they keep trying to keep a track when I'm a loser in their eyes?
I do have a lovely girlfriend and I'm not unhappy with my life, but I want to be over with those old people who Hurt me.

[tattooedhandfet]

If someone stalks you online. The only real way you can stop that from happening, is to just disengage.

[Asker]

Absolutely. But why do they do it is what I wish to know...