Metal is anti-trendy on the whole, yes. The current global trend is to make your music the most infantile and easy to access as you can possibly get whether or not it sounds exactly the same as everything else on the radio etc. Metal, has it's own little trends, yes, but on the grand scheme of things it's polar opposite to the common "three chord, drumline only, faggot lyrics" that personify the common music of today.
In a sea of girly EMO bands, neo-punk, rap and rap-rock, that bow to the "I R dumn" trend with the same crappy lyrics of, "I fucked her in the ass," "I miss/love you so much," and, "I can't believe that bitch left me," along with the lack of any musical prowess in writing and playing a band like At The Gates is completely flying in the face of the common trend.