are sororities this cutthroat?

As an outsider looking in and a freshman considering rush, I want to know if being in a sorority is really all about rank? My mom was in a sorority (Tri-Delt, not here) and I get that there will always be cliques, but she has stories about hanging with her own sisters, as well as sisters from lots of other sororities. Shr's always said that the best part of being in a sorority was feeling part of a larger community of "Greek sisterhood." This site was suggested to me as a way to get an idea of the Greek scene and players here, but all I read are nasty posts of one sorority dissing another, how X is better than Y. Is there really this much rivalry? And if so, why can't you all get along? The overall system seems cutthroat, and honestly I'd like to know before I rush if this is what to expect because I don't think I'd want to deal with that. And yes, this is a legitimate post.