The fact that the build mainly uses greyscale is a matter of style, it's not that it was stereotypically chosen to create a lab in greyscale just because laboratories refer to use dark colors. As you may see, even the books in the shelves lack colors. This should testimony of the peculiar chosen style the build possesses.
Another thing that makes the use of greyscale a valuable thing in this build (that hopefully will rely on gameplay and exploring abilities) is how you can highlight certain things without letting them fall into oblivion. Doors, switches, keys, buttons and certain objects or maybe even easter eggs are thus easily noted, easily appreciated and more or less better looking.
I seriously love the use of greyscale and find it an artistic and smart move, but I can understand if people are negative to it seeing they are fed with mlp every day. :)