There's no universal, objective agreement about when exactly your Martians are blue or green.

That falls under "lossy compression". There are certainly Martians who are considered to be green in the majority of interactions with humans, and other Martians who are considered to be blue in the majority of interactions with humans.

And you're still neglecting the fact that humans tickle Martians.

1) Humans don't tickle Martians as much as Martians tickle humans. (Women don't approach men nearly as much as men approach women, and aren't expected to.)

2) Humans who tickle Martians tickle blue pretty much all the time. (It is acceptable for women to act as though a bad pickup attempt from a man is a threat; it is not acceptable for men to act as though a bad pickup attempt from a woman is a threat except for the most extreme cases.)