You're always in AoE range if you have hate. That's pretty much the simplest answer. I also have a tendency to walk into AoE range to avoid screwing with my DDs by pulling the monster away and making them lose TP mid-WS. Even with Wildfire's Enmity- buff, I'm gaining hate about as fast as the Ukon/Vereth combo we have tanking most of the time - especially when they change to proc weapons and I don't.

I also have to be within 16' any time I want to roll, so it's just more convenient overall not to stray too far away from the monster. I prefer to stay at 12-14' if I have the option, which is enough to run out of range of AoEs if I need to, and close enough that I can run into range quickly if I take hate or know I'm about to take hate, as I dislike making the monster turn and run away from the DDs.