the thing is that we don't always start working on sites from scratch. more often I have to clean up someone else's mess or my own that I made months or years ago. in that case I'd rather debug javascript than css.
Yeah, I think it's a lot easier to fix shitty JS than it is to fix shitty CSS. Every job I've had, I've fixed more than I build. If it's a 5 person startup, I'm iteratively fixing my own shit as the product pivots. If it's 30 people, I'm fixing code from that one idiot that interviewed well and turned out to be impressively terrible. If it's a 10,000 person company, I'm fixing shit from that entire division that wasn't properly managed.
my entire career in 2 lines
On the contrary, I think it is a lot easier to fix shitty CSS than shitty JS, because CSS is not run, but specifies attributes. This makes analysis static for the most part; race conditions and similar bugs usually do not occur.