Not to justify this creep, but it sounds like his victims thought they were doing something consensual (possibly for cash?) and didn't know what Broomas intended would be that bad. They're lucky his perversion was channeled and he didn't kill them.
It doesn't take ignoring a "safe word" for that line to be crossed. Remember that there have been several incidents of men who consented to have their penis cut off by men they met over the internet. One guy even agreed to to being murdered. Just because you consent does not make it "legal".