See, this makes sense to me. It’s the same way with anything IMO. If it involves bodily fluids, beyond native saliva and tears, you probably want to wash it specifically. At least in its own load, possibly in a different machine entirely, maybe even get it professionally handled, or clean it with fire. Depending on the severity of the soiling…
I have no issue with someone using a thing that was designed for another purpose to do something that it’s designers didn’t think of. As long as you’re not cross contaminating your food with it, I couldn’t really care less… But bluntly, using your dishwasher, the same one you use for dishes, to clean your poop scrubber? Big nope from me.