To figure out why people like Dubstep, you have to consider why people like music at all.
Music is all about timing, and allows the listener to categorize time in real time. It basically gives people a tangible way to perceive time, which when played to a large crowd gets everyone's brains working in a similar fashion. Humans, being social creatures find this pleasurable, to be in tune with such a large group.
The second reason people enjoy music is because it is predictable, music starts with a base rhythm, and gives you enough time to learn the pattern before introducing a new pattern over top, and so on and so forth. Slowly the patterns get more complex. People enjoy this because their brains automatically attempt to predict the progression, and actually release reward chemicals when the prediction is correct. It quite literally produces a high. The more complex the pattern the more complete the high. Some frequencies even stimulate the areas of the brain that perform this function, allowing the listener to "sync" themselves with the music. Combining this with point one makes good music a highly pleasurable and spiritual experience.
This is why bad music, or music that does not appeal to someone's tastes can actually generate feelings of frustration and hostility, because the brain finds itself unable to compute the info, or simply overwhelmed with stimuli and gets frustrated.
Familiarity also plays a factor, for some reason the more a person knows about the music, the more they enjoy it, which is why some pop artists have such a huge fanbase in spite of their scandals, because the more the audience thinks they know about the artist the more likely they are to enjoy it, though this is a double edged sword because people who find their morals in conflict with the artists are more likely to avoid their music entirely.
With all that in mind, I can conclude that people(myself included), enjoy dubstep because it is designed to appeal on the structural level. The timing while often bizarre is predictable, but quickly becomes more complex, and generates frequencies which actually affect brain function. The noise is often new and strange and gives a sense of discovery every time the music is heard. Additionally familiarity comes into play because anything(and I mean anything) can be dubstepped, video-game soundtracks, movie soundtracks, quotes, voices, anything, thus allowing it to appeal to a wide range of listeners.
The biggest problem is that dubstep can be too predictable, and the noise can overwhelm the listener and exhaust their mind to the point of frustration.