Since D&D care nothing about spoiling book readers, I feel like having a massive campaign to spoil the big one in ep 10. #GameofThrones— Linda & Elio (@hippoiathanatoi) June 8, 2015
Essentially, they're mad that despite their Big Name Fan status, GRRM disclosed what they view to be spoilers about The Winds of Winter to D&D and not to them. And they're calling everyone who's questioning them "retards" and "cunts" and blocking them. The replies on that status should give you some idea.
Who are these two, by the way? I'm glad you asked. Basically, Lindaaaa and Elio run westeros.org and are pretty chummy with GRRM himself. They helped write The World of Ice and Fire (the encyclopedia) and some fans believe they heavily influence Gurm himself with the story. Lindaaaa in particular is not a nice person at all, and here is a master post detailing why. She's racist, misogynistic, and all-around completely over-the-top, unprofessional, and childish. She absolutely despises Tumblr and ONTD (because we're chiefly female fans of the series) as well as fanfiction. She compares fanfic to pedophilia. That's all you really need to know about Lindaaaa. Oh, except for the fact that she believes literally every character in the books is white and should be cast with white actors.
There's a pretty big thread going on at r/asoiaf right now about this drama if you want more. This reflects extremely poorly on GRRM and the publishers (since Lindaaaaa and Elio are co-authors on a book with GRRM) and is a PR nightmare that I knew ONTD would enjoy.
Source is Twitter.