Not opportunists
These companies are not opportunists, other ISPs are simply not collecting money they are allowed under the law to collect. The FTC does not do it's job of pursuing spammers at any realistic rate, so a few ISPs make it a point to do so. Spammers, guess what! If you don't spam, they will not sue you!
As for this judgement, it's a shame, but really if no information turns up they should have given it up and let that one get away far earlier.