Given enough protein, with the same calories and activity levels, I see little difference in fat gain. The point of eating clean is not to minimize fat gain, it is to keep yourself healthy with regards to cholesterol, etc etc.
There is one guy I know who is a good example of why eating clean is not necessarily always a good thing. He's about my height, has been training for like 8 years... stalled out at around 170-180 lbs. He's not very lean, you can't see his abs. Yet in 2005, I went from about the same weight as him to about 215 lbs. That's only one year with HST and eating enough food. My bodyfat got sort of high, but not too bad. My abs are still sort of visible, just quite blurry.
What was the difference between us? The difference was that he ate clean, so while he was eating a large amount of food, just like I was eating a lot, his total calories were much lower than mine. Just one three month long bulk eating the way I did would probably have changed his body quite a bit...
A dirty bulk is not going to hurt you. I just had to get checked out by my doctor and he said my cholesterol, blood pressure, etc were great. That's after just coming off a four and a half month long bulk, eating plenty of calorie dense foods.
What you need to do is make sure that you don't let your bulking diet become your year round diet. As long as you maintain sensible eating patterns during the rest of the year, you will be fine. I guess if you have some sort of genetic predisposition to high cholesterol, then you'll have to be careful, but those types of people tend to have bad cholesterol no matter what their diet is.
Anyway, like Dan said, it is a misuse of labels. Really, what it comes down to is that you should be eating healthy. I advocate eating healthy, though like I stated, I believe it is okay to put healthy eating on hold during the bulking months...
Most guys in our arena always supplement with fish oil, multivitamins and protein powders, so getting enough nutrients should never be a problem, whether eating healthy or now.