Njaff... yiff is for fun, same as ***, hentai (it rocks too <3) or whatever. If someone like it, it's his own business... so topics like this are practically useless, what you gonna prove by saying "OMG, look at me! I hate yiff! Now I'm trollproof and cool, I'm sooo pure and innocent, gonna beatify myself!"
One last word: chill ;3