One day you'll grow up and realize that Vriska is cool.

Anyways, Homestuck's length is the primary offender. The larger and more complex a story gets, the more it has to appeal to a prospective reader in order to bring them in. Look at this from the opposite angle: short-form video content is widely popular because if you watch one or four mediocre shorts, that's like a minute wasted at most. Homestuck was written over the course of eight years and would take like a week of treating it as a full-time job to speed-read through.

After that, it's the subversion. Homestuck loves to throw people for a loop. Be it switching to another character just before something big is about to happen or setting up for an expected outcome only for it to blow up in everybody's face. "What is Homestuck about" is a difficult question because the characters will be certain that Homestuck is about x for months before finding out that x was never going to be the primary focus.