am I unusual in not really seeing the "creepiness" of zalgo text?

Maybe you missed this piece of the internet history: https://stackoverflow.com/a/1732454

Think of it as representing something like the letters actively 'creeping' and giving off tendrils of darkness. Does this help?

I understand the idea, it just doesn't impact me

It's not inherently creepy but often symbolic of corruption or someone talking in a raspy/synthetic "evil overlord" kind of voice.