This is basically just a "we shouldn't have cars because it would be bad for carriage and buggy whip makers, and they'd be less happy if they had to find other work" argument.
The short version is that the people upset about this stuff have also benefitted immensely from lots of other jobs being automated away and thought they were immune until the first image generating models hit the scene. Now they fear the same thing that happened to a lot of manufacturing jobs, except it's a problem now because white collar work and creatives are supposed to be immune.