If you are interested in logic at ALL than this fallacy is likely one that frustrates you often. For that reason it is hugely exciting. The relativist fallacy occurs whenever someone says: "well that is true for you but not true for me" and the topic is not actually relative. Of course that is total bullocks. Go to the fallacy section for more info; I have included some explanation in both the Vegan and Omnivore sections, because I have seen people on both sides employ this faulty logic. Those poor souls.
The next time you hear someone say this above falsity, please give them an intellectual slap for me (not a real one of course). This is a fallacy that pops its head up sooooo much that, one cannot help but loathe it utterly.