Hellsing Ultimate OVA series.
It is perfectly legal for Sony to use OSS in their proprietary software, so long as they give proper credit for it, which they do. The point being is, don't think Sony did not edit the software they used. Just because the credits include FreeBSD, does not mean the put in a vanilla FreeBSD build into it. In fact everything is probably highly edited to suit the needs of the PS3's OS.
The point of OSS is freedom of information and the freedom to use and distribute the code. That includes using it in/with proprietary software. So Sony did not do anything wrong here. They did not do anything immoral by using OSS.
Another thing is that Sony, Samsung, Microsoft, etc. have contributed quite a bit to Linux/Android and other OSS. Don't assume they are just using whatever they can, never to help out.
My statement above was that reDRM dongles should not cost money, in fact, they should not exist. Their work is already illegal, but they are putting a price tag on it. Sony would sue them if they could, I would not doubt that, but they are probably well hidden or there isn't enough evidence on the people that are involved to warrant a case.
Why would Cobra do that? They already have it implemented in a CFW, it is just reDRM'd using their dongle. The dongle's only purpose is to be checked by the CFW whether or not it is inserted into the USB port. Nothing else. Cobra wants your money, just like Sony wants money. They're no better.