Yes, trolls. They thrive on attention. Ignore them and they wither on the vine. I think all forums that I have ever been a member of have an ignore option within the control panel. Hit that button, ignore the brat and he'll pack up and move off. Keep letting him (or her) push your buttons and he'll stay around getting ever more obnoxious.
Sad life it must be really if that is how you have to get your kicks. More to be pitied than scolded as my dear old granny would say.