They don't cause centralization.
Really? So you think that one person/group controlling 1000s of mining machines where they can achieve more than half the hash rate isn't centralization?
nope.
I see.. Well either you're not all that bright since that's exactly why Satoshi designed what he did, or you have an ulterior motive for spreading that fallacy. Either way, not like it really matters since it's all going to end up being centralized so good luck to you.
I am far more concerned with a bad actor that controls asics than a botnet owner trying to 51%. You see the botnet owner will not kill his income while whoever can afford the asic ranch may very well be an incentivized adversary. You can figure out the rest yourself unless you are the dullard you think i am.
You said a botnet having 50%+ wasn't centralization. Now you're twisting it into what they'd actually do with that centralized control so you can try and "win" an argument that you just lost with that tactic. We can certainly have a discussion about what someone might do with centralized control. But that's different than the fact that they have it.