While I agree with the general sentiment, I would not classify Dolby as a "patent troll" — they still do invest in research and developing products, right?

I'd classify any patent racketeer as a troll. Dolby has nothing to do with AV1, they just want a parasitic rent on it. Whether the troll actually does anything else besides the trolling part isn't really relevant.

Patent mob seems more fitting.

Another example is Qualcomm