Okay I'll bite. How is your choice of device the dev's responsibility?
I mean it's not like it'd make sense to flame blizzard or bethesda because you can't play as long as you'd like on a laptop/mobile.
You use the proper device for the proper use, and this way you just get an additional option to trade value with the site owner. You're free not to mine in the same way you're free to get a paid account if you don't like ads.
That's not "the big problem" in my opinion. I don't even know if I would consider it a problem at all. If I want to drain my computer's battery and get something for it that's my choice. As I said in another comment, the actual big problem is rogue sites putting this crap without user initialization or even informing them.
I mean it's not like it'd make sense to flame blizzard or bethesda because you can't play as long as you'd like on a laptop/mobile.
You use the proper device for the proper use, and this way you just get an additional option to trade value with the site owner. You're free not to mine in the same way you're free to get a paid account if you don't like ads.