Hell, they'll give you this look even when you say you like Iron Maiden, Judas Priest and of all bands - Motorhead.
People have particular subgenres of taste, but who the hell decided at one point that we should evaluate what is metal and what isn't?
I have given bands like Cannibal Corpse, Death and sprinkles of other Death/Black metal bands honest tries. To me it's all just noise and the vocalist guarantees me that I will not like them because it's just belching and barking lyrics.