@husky @backdraft7 start adding those domains to your disavow list.
My established pr4 site has 100's of thousands of bad links pointed at it. I've spent a lot of time disavowing and having to go out and look at these gross sites to make sure they're bad.
It doesn't seem to have hurt me thus far, and today I just jumped over the SOB whom I am certain pointed those links at me.
Coincidentally, I noticed that someone (who shall remain nameless) recently went to Fiverr and pointed bad links at my competitor, shall we say, return the favor. At least the field has been leveled and Google now has to sort out all of the sites in my niche because we all have these links. Fair is far, although it really really sucks.
I really think that my rise over my nasty competitor was due to my having much better content than him, and not due to bad links. After living in this bad-seo space for a year now, I suspect Google has a handle on this. They have to be discovering millions of these links every day, and seeing the same domains across thousands of disavow lists... how could they not know.