DJ's lack of popularity demonstrates the ignorance of fight fans.
Demetrius Johnson just defended his title for the 9th time, putting him 1 win away from tying Anderson Silva's record for consecutive title defenses. He currently has the same number of title defenses as every other UFC champion combined and has finished 5 of those defenses (Stipe & Joanna have one finish each, all other champions have none). Not to mention that he's undefeated at flyweight, and was a top contender at bantamweight while he was still working full time in a warehouse.
Despite all of this casual fans barely know who he is and a lot of dedicated MMA fans still try to discredit him for being boring. Reasons for disliking DJ include:
1.) I don't like watching little people fight, I could probably beat them up (just FYI, you can't).
2.) He isn't a draw and I only like to support people who are popular.
3.) He never talks any trash, and I cannot enjoy a fist fight between two grown men unless I know that they really don't like each other.
DJ has everything that MMA purists love (IE he puts on great fights and he's pretty much the consensus P4P best fighter going right now according to most experts), but MMA fans continually prove that fighting isn't the most important thing to them.
I will admit that the UFC's poor promotion of DJ and the flyweights in general plays a big part in things, but if watching quality MMA fights was the most important thing to UFC fans they would be going out of their way to watch Mighty Mouse.