VFX engineer here. Yes we used to cailbrate monitors and work in the dark.

However one of the key people that built our colour pipeline was also colour blind, so its not actually a requirement, so long as you use the right tools.

Most people aren't that sensitive to colour, especially if its out of context. a minority of people aren't that good at relative chromaticity as well (as in is this colour bluer/greener/redder than that one) But a lot of people are.

Language affects how you perceive colour as well.

But to say the experiment is flawed I think misses the nuance, which is capturing how people see colour _in the real world_. Sure some people will have truetone on, or some other daily colour balance fiddling. But thats still how people see the world as it is, rather than in isolation.