Why do people think all guys are jerks?

My boyfriend is like the sweetest person ever and people keep telling me that he's going to turn out to be a jerk...?
Are all guys jerks or are there exceptions?

All guys are not jerks. My boyfriend and I have been together for 3 years and he is still not a jerk.

The people who tell you he's a jerk --- are they suggesting you date a woman instead, or another type of guy? What has he done to deserve this label?

Their really only talking about the ones they've met and been dissapointed by. And who are these people anyway? Telling you, your boyfriend will eventually turn into a jerk - They don't sound like friends to me. Its your life and know one elses business so does it really matter?

They are my best friends lol.
No but with the experiences that she has had, all the guys have turned out to be a jerk and its just a commonly stated thing