It's quite simple, really. They go along with it because it's only disarming someone else. That's how anti gun laws have always passed and been tolerated, and largely how taxes are passed too, as it's someone else's rights and someone else's money that's being sacrificed. 1850's-1870's gun laws were tolerated because they were disarming blacks, so nobody who wasn't black objected at the time. In 1911 NY's Sullivan Law was tolerated because it was intended at the time only to disarm Italians, so anyone who wasn't Italian had no problem with it because it wasn't them. In 1934 the NFA which ostensibly disarmed mobsters, which since the public sees themselves as not, they had no problem with that either.
Fast forward to today. Today, it is the same class or race based hate simply channeled in a different direction. Gun ownership is the new villain for society lacking a moral basis since the 1960's, before which they could rely on actual standards of right and wrong. Now it's conservatives who are being disarmed, they think, which they are not. Gun owners, which they being city people are not. Or rednecks, which they are not. Or racists (by their definition) which they tell themselves they are not. Or hunters, which they are not. Or, often in the case of feminists and metrosexualized males, traditional American males, which they are not. Gun owners have become the "undesirables", the outcast class which is fashionable to deride, smear, and abuse with restrictive laws, for which all of society's ills can be blamed, and the public can say "Well, at least I'm better than them, keep those eewy sub-people away from us!"