For me it's less about fear and more about having a limited budget of time and effort to spend on learning things, so CSS and front end generally gets deprioritized. But that's cuz I'm a back end kinda dev in my soul, lol.

I've seen the good points you've made elsewhere in this thread - I would indeed react very poorly to willy-nilly back end changes and I think you're right that people don't give CSS and visual styling the same degree of professional respect when making changes. And that sucks.