The greys in Deus Ex were never intended as actual greys. The designers have said several times that they were used to divert attention from what was really going on at Area 51. They were more or less a diversionary tactic, meant to discredit anyone who tried to leak MJ 12 secrets. Bob Page and co. probably knew what they were, but most scientists and engineers were in the dark about it.
Sen
Topic
08:39:24 AM Oct 13th 2011
Why do we always assume aliens look humanoid? Anthropocentrism much?
RTaco
11:29:00 AM Oct 13th 2011
Yup.
Pichukun
Topic
05:51:12 PM May 30th 2011
Grey? I typically see them green in works. Is that a different trope?