To answer your questions in order, I VERY rarely read about abcesses AT ALL ANYWHERE on these boards. I read a few isolated posts from kids who THINK they MAY have abcesses but then it turns out to be just swelling. I personally am not aware with anymore abcess cases coming from ug gear as opposed to human grade gear. I believe that most abcesses occur simply due to poor injection procedures.
As far as inconsistent dosing, I believe many of those tests were done back when powder suppliers were mostly middlemen. Now that "factory direct" powders are a reality, I believe tests will become far more consistent. Now there will always be a lab or two who tries to overdose things to a huge extent because they think it makes them look good. But if you do it correctly, you should easily be within 5% of the intended dose.
As for why they use more complex processes to sterilize their products, I can only imagine this has to do with guidlines set by their respective governments. And just because the gov't says that's what you have to do, doesn't mean it is what's necessary. I think everyone on here should be at least FAMILIAR with governments beaurocracy
Lastly, I do not BELIEVE that is all that's needed to produce sterile products, I KNOW that is all that's needed. That is why I do not in any way consider what I buy "taking a risk." If I did, I wouldn't purchase. But in two years with the same 1-2 guys (not to mention occassionally making my own), I have yet to have a single problem, nor have I heard of any problems. As such, I feel it's a pretty safe bet.
But in the end, if people feel like spending 2-3 times what I do for the same products, who am I to tell them not to?