It may be easier to type and say (as are most words in comparison), but "antidisestablishmentarianism" has a well-defined meaning that would make for a less-vague rule. "Bootlicking" means a lot of different things to a lot of people, and not all of those people have common sense, to put it nicely. I've been called a bootlicker for saying I don't want to tear down the entirety of every government everywhere, ever, for instance, which I imagine isn't what that rule is trying to convey.

There's a reason "legalese" is the language laws are written in. It's very specific, with any potentially ambiguous words given clear definitions before any of the rest of the law is presented (at least that's the intent in the US, anyway). If you were to, say, define "bootlicker" in the beginning of the rules to mean "excessive praise for police violence," then I'd say it's quite safe to use elsewhere in said document. Leaving such a vague word undefined in what amounts to a paralegal document opens up avenues for abusive interpretation, both from moderators and community members.

TL;DR: Clear definitions of what your rules mean leads to a healthier, easier to moderate community overall.