I think there's a huge difference between an intentional allegory used as an attack on a marginalized group, and a word being used to durogatorily refer to a non-living, non-feeling group of machines which are actively damaging the world.

yea, i guess someone saying "screws will not replace us" or "13% of the code, 50% of the bugs" (both real things i’ve seen people say)

I would agree that these things are not okay, becuase they're imitating insults that literally only exist to put forward racist ideology, and I'd tell anyone who used them around me as much.

cause it’s the same shit with clanker and other assorted nonsense, you’re making racist jokes but swapping racialized people for an acceptable target. but guess what, it’s still racism! you’re still doing a racist joke!

So, how about "chud" then, intended to refer to right-wing-minded hate mongers? Or, here's a better one, how about when we call right-wing extremists nazis as a durogatory insult? I mean they're certainly not all members of the third reich. We're using the term to equate them to something they strictly aren't, even if they share more ideology than is okay. We're still using words to categorize groups of people, and using them in intentionally insulting ways. Such durogatory terms are a part of our natural language. They're not nice, sure, but I don't want to be nice to people who are actively calling for violence against marginalized groups. But most importantly, we don't think of these words as slurs. Slurs are durogatory terms that target marginalized groups, unlike "chud," "nazi," or yes, "clanker."

I think there's far too much nuance here to make blanket insinuations like "durogatory terms used to refer to things we don't like are stand-ins for racist remarks." But considering some of the other connections you've seen people make, I can certainly understand the trepidation.