It's interesting that this sentiment almost exclusively comes from people with almost no knowledge about dark matter.

What do you think is more likely, there is a theory that makes all observations look exactly like there is invisible matter without actually being invisible matter, or that there is invisible matter? I am going with the latter.

I also do not understand why laypeople are of the opinion that all massive particles must interact electromagnetically. If you are open to the idea that there is a massive particle that doesn't, you got dark matter.