Each album put out breaks the base a bit more, but then came That's The Spirit... Oh, dear god.
Critical Dissonance: They are praised highly by musicians and critics, but not even getting praise from Rob Halford (yes, the Metal God himself) seemed to stop them from being hated by at the very least half the metal fanbase.
Dead Horse Genre: In an interview, Oli Sykes said that Deathcore has become one, hence the band's Genre Shift to Metalcore for Suicide Season. They would later cite this as the reason for them abandoning metalcore completely for a radio-friendly electronic rock sound.
Face of the Band: Frontman Oli Sykes. Lots of his female fans don't even listen to the band (or heavy music at all). Also, it isn't terribly uncommon for an attempted conversation about the band to go a little like this: "Hey, uh, you ever heard of Bring Me The Horizon?" "Oh man, I hate/lovethat guy!" That said, former guitarist Curtis Ward was pretty popular as well, probably thanks in part to being a bit of a Large Ham like Oli.
He's also shared the Face role with Jona and Jordan.
Follow the Leader: While the band themselves have been accused of this, they also have their share of imitators, being one of the first bands to bridge the gap between floppy-haired Metalcore and the Darker and Edgier Deathcore scene.
Definitely started happening to them when Sempiternal came out. Suddenly a bunch of metalcore bands started mixing their sound with electronic music.
Germans Love David Hasselhoff: While certainly popular in the UK, their American fan base might be even bigger. And yes, they're big in Japan too.
They're also quite popular in Australia, with their last 3 albums all debuting at #1 on the album charts there.
Growing the Beard: Each and every album by them is better than the former. There Is A Hell... There Is A Heaven has been lauded as this by journalists. Sempiternal even more so. Of course, whether That's the Spirit continued the trend is still being debated.
Harsher in Hindsight: The song "Deathbeds" is a duet between Oli and his then fiancee Hannah Snowdon about how they would spend the rest of their lives together... except their marriage lasted a little over a year before Oli apparently caught Hannah cheating on him.
He Really Can Sing: It took four albums, but Oli finally sang clean vocals on Sempiternal. It was worth the wait.
Internet Backdraft: Just the sheer mention to a metalhead will cause you to be accused of being a poseur. To the point where the Metal Archives can't even list them, or bands even similar to them. And then some.
Newbie Boom: They are a case of this for metalcore, essentially providing the breakdown-loving Emo Teen crowd that would go on to fuel the entire second wave of metalcore (Especially in the UK, where metalcore never made a large impact to begin with).
Nightmare Fuel: "For Stevie Wonder's Eyes Only" aims for this with such lines as "I whispered in her ear: fear me, dear, for I am death".
The song itself is bad enough, but their fates in the "Alligator Blood" video:
Oli getting the "Death" card, then suddenly convulsing and dropping dead from what appears to be a heart attack.
Jordan being left to freak out with a spider on his chest.
The Scrappy: They are currently one of the most hated bands in the metal scene, if not one of the most hated metal bands in history. It's very hard to find a metalhead trying to defend them, and even harder to find one who admits to being a fan. You'd think that as a band that so few metalheads claim to like, that they'd get less recognition. The reasons behind their strong Hatedom aren't exactly known, though.
BMTH has actually matured and refined their sound very much since their debut, and as of now they are actually a very mature and nuanced band with a strong sense of song craft. Their hatedom does not seem to descend from their music, but from their image, since metalheads tend to hate metal influenced bands with a non masculine image. In fact BMTH is currently one of the most innovated and experimental metalcore bands in general as of Sempiternal, and is probably one of metalcore's biggest Ensemble Darkhorses.