Main reason I mind is because DRM a) creates "artificial scarcity" of an effectively "infinitely" and freely duplicate-able resource (digital bits of data) mostly to fulfill the bottomless greed-hole of corporate entities (rather than to enrich the original creator for
their part in it), and b) (and this is the main reason I hate DRM) because it gives some bottomless pit of greed corporate entity the ability to arbitrarily deprive me of something I paid for, or restrict my ability to use / access it at some unknown point in time down the road, forcing me to maybe have to pay
again for something I already paid for. (Nope. Not gonna do that. If I'm backed into that corner, I'll choose to "fly the Jolly Roger" and acquire a DRM-free copy some other way.)
Given the option to support content creators in some way that doesn't screw me over as a content "consumer", I'ma prefer that option all day long, every day; However, too many corporate entities these days would rather not offer that option, if they think they can find a way to make you pay every single time you lay eyeballs on something… (That is the ultimate goal of some of 'em, to be certain.)