Eh, it really depends on the person, as long as they know what is fantasy and reality, they can enjoy such fetishes. For instance, ponyfags like MLP, however would they mate a horse in real life? I doubt it...I think. Anyways, it's practically that, it's there for a reason, to tingle our minds on certain scenarios, and it's basically the curiosity that peaks our drive, to think of new things, but again, as long as you have enough IQ to differentiate them from reality, you are free to enjoy whatever your deep dark desires are as long as it does not harm the people near you. And you never know, maybe because they are not that endowed with height that they feel like they need to find some porn material that can relate to him/her, true there are some who wants giant girls, but what of those men who want girls who are shorter than them or vice versa? Enter the loli, shota fetish. Anyways, a human psyche is a fun thing.