It is well known that Muggles would never stand a chance in a fight against a fully trained adult Wizard. Right? Unless, of course, they used MUGGLE ways of fighting back... like, say, oh... snapping a certain Dark Lord's wand in half? Can you say "oops"
They were once the most powerful people in Europe, full of the conviction of their own natural superiority to the point where it seemed they'd become immortal. They'd eaten death, and they longed to taste it again.