I think that's because the Weasley's are the retarded white trash of the wizarding world.
I never understood the Ministry. So they answer to the Prime Minister of the UK, who I assume is a muggle, but correct me if I'm wrong, but in the UK doesn't the PM pick who is the minister? So he could have picked anybody, like another muggle to be the Minister. Also doesn't that mean that like at least a couple of hundred muggles know about the magic world at any given time? That's not even counting the muggles like Hermoine's parents who are the normal people parents of a wizard, and so on. So logically a shit ton of the UK knows about the wizards, but pretends they aren't there, and no general or admiral has ever tried to weaponize the fact that the largest magic school in europe is in Scotland? Also doesn't this make the Wizgamot or whatever the hell it's called, pointless? SInce all the powre flows from the muggle PM through the minister of magic? And so on, and so on, and so on.
Yeah, I guess Rowling's world building sucks.