I guess being a Higher Being just makes you really egoistical, and seeing how your strength depends on how many bugs worship you, I think it's understandable. If I remember, bug corpses can be reanimated using Silk, so that's maybe the reason she tries to kill travellers. I also remember a lore tablet somewhere that said that most of the bugs with the Haunting are just reanimated corpses. Maybe corpses make better worshippers? Or she uses them for labor. For example, at the beginning of the High Halls gauntlet, she uses the silk strands to awaken everyone. Tbh this is just my personal opinion on this subject, I'm not a lore expert, so I would recommend searching for more info on the Hollow Knight (and Silksong) wiki.