I don't see how Hotaru's crush on Komari was disturbing really? SHE is the one who is a lot younger - and the other party is childish and also totally unaware. You can say Hotaru was excessive, but I think obsessive is a bit unwarranted.
She is mainly hung up on how cute Komari is and making lots of plushies, but her behavior when with Komari is generally pretty normal. I think her behavior was mostly innocent and childlike not disturbing or yandere like at all.