"its funny to me how many guys here think the guy who cheated is supposed to be given a free pass and the girl should shoulder 100% of the blame"
If the guy is completely random and doesn't know you and isn't trying to send a message to you with it then that guy shoulders pretty much none of the blame for a cheating wh0re girlfriend and indeed should be given a pass.
100% of the blame for cheating belongs to a chick because without her consent no cheating with other guys could or would happen and people with class and a sense of decency just do not cheat rather if they are not digging a particular relationship they are in they will end that relationship before persuing things with any other person and I mean no one will have been in your ex girl's radar until she ends the relationship with you first if she has any class or decency at all.
So yeah a random guy coming along and getting it on with your cheating slvt of a girlfriend is just doing what any guy would do and if he's a random guy he's got nothing against you he's just trying to get a nut from a willing chick thats all so its pointless to hate on him for this.
An enemy of yours though or someone thats got a problem with you that goes after your chick just to get to you I would agree deserves an ass kicking but yeah again a random guy is just doing what any guy would do unless say that guy was ultra moral like the poster The Humanist and who knows maybe even The Humanist would smash on someone's girl if she was hot enough and wanted him.
Edit: Actually I just re-read the quote and if you meant to say its wrong that people here think its alright when they cheat on a chick that this is bad well all I can tell you is this whole site is about helping men benefit themselves first. Its not about fairness. Its about getting guys the best deal possible from every interaction with women and the common and I think positive rationalization for this is that most of today's women are this cutthroat so why not be better at their own stupid games than they are? That way you are not likely to be the one with egg and pie all over your face when all the smoke clears and all the dust has settled on whatever relationship/fvck buddy scenario.
"for real, thanking other guys for fvckin your girlfriend and bringing unneeded drama into your life."
Yeah T!ttyman already explained its not necessarily a literal phrase but it can be and what it really means is if you are in a LTR and some guy comes along and your girl cheats with him you are figuratively thanking him for alerting you to the fact that your girl is a cheating ho and thus not relationship material and he also gets thanks in a figurative sense because he helped you dodge a bullet in a few ways and those ways are 1. You don't waste any more of your valueable time with this slvt and 2. Because you don't waste any more valueable time with this slvt you don't eventually make the mistake of marrying this cheater someday and having an even more brutal ending to things when she eventually cheats on you during a marriage then you have to divorce her and give her half your sh!t even though because of her cheating she doesn't deserve anything. Though I think there are some states or maybe many now that have marriage laws where if its proved one of the partners cheated the other one doesn't get anything in the divorce settlement.
Anyway though some guys do literally thank the guy that made them aware to what their woman really was and I think guys like that have a tremendously strong inner game and most other guys without that level of game don't actually thank the guy who does this but they still learn from it and despite the situation being negative they take the same positive lesson away from the cheating having happened.