Honestly, I'll be the first person to admit that JLB's voice took some time to grow on me, but when I first heard the music, it blew me away. So much so that I said, "This music is worth listening to, even if I have to tolerate the vocalist." And yes, at the time, I was very much in the mind state that associated Metal with heavier, and lower timbre vocals. And higher timbre vocals, like JLB's normal tone, I often associated with the Skater Punk genre, which I hated, so that was a bit of a barrier for me.
Either way, the point is, the music was great enough to keep me listening, and as time went on, JLB has become one of my favorite vocalists ever. He's got a very unique vocal quality, and people who aren't used to it have a harder time enjoying it, because their ear isn't really accustomed to it, so it's almost jarring in a way, I think. But then again, the very nature of DT's music is like that. When you first hear it, the crazy time changes and weird structures, it's a bit jarring at first too. So all of it takes time to grow on you, but once it does, it's there to stay.