I've talked to a lot of engineers building DRM technology, and most of them are just a combination of swept up in the fun of the challenge, and also deeply bought into the idea of protecting intellectual property. I would say probably 90% don't see any philosophical issues with what they're building at all. If you can convince them of that, quite a few of them would probably try to get out, but it's quite an uphill battle. I forget who said the quote and the exact words, but something along the lines of it's very difficult to disabuse somebody of a belief when their livelihood depends on believing it.

As someone who was in an industry that I later discovered was doing things I wasn't personally ethically okay with, I would advise them to do similar to me. Start looking for a new gig and just get out as soon as you can.

Unfortunately as an individual there just isn't much you can do. There will always be someone willing to do the job that you aren't willing to do. Just get out and find something you can sleep at night doing