If I tell someone to move their car because they’re blocking the bike lane, I’m not inviting a debate about whether it’s a good idea to have a rule like that.

To be fair, most people doing stuff like that know very well, why the specific rules exist, but do not care, and are intentionally breaking them. In this example, if you have a driving licence, I image in most places they require you learning the rules of traffic, so they can be assumed to already have the knowledge. If they cared about the actual specifics of the reason, they would have asked, when they had to learn about it: thus them demanding answers for the rule on the fly, should also be assumed to be dishonest.
And also in this example, if you are unable to figure out on your own, why you should not endanger bikers, by putting huge metal obstacles, with suddenly opening doors in front of them, means you should not have a driving licence at all.

They always have some reason, they think is good enough for rule breaking - and might be, like some medical emergency or something, but those times would normally be solved with a polite discussion anyway, after the situation allows it - but usually it is just them being selfish morons.