Too many of them don’t have the guts to take an honest good hard look at the world and see it as it is, rather than as they wish it were.
eg. in the real world there are bad guys who don’t obey laws. Ergo disarming the good guys is doing active harm since the bad guys aren’t going to obey gun laws anyway. In their fantasy world, they’re always just one ban away from utopia.
Gun ownership, like foxes and rabbits, can be cyclical. Bad guys with guns give good guys incentive to have guns. Good guys with guns provide less incentive for bad guys to have guns. Bad guys without guns lessens incentive for good guys.
Same cycle can apply to conservatism/liberalism.