Why do some single guys harass maried women?What part of "I'm married" don't you understand?Some jerk actually told me I bought the ring myself,insult.

because,to them,the unavailable seems more appealing

To some men,it is believed to be safer in the sense that a married woman will be more discreet about it than a spinster.
Also,she will by all means avoid unwanted pregnancies unlike a spinster who may deliberately get into it and keep it.
Many who do it seem to enjoy stealing and eating another man's fruit

Some do it to boost their ego.