I don't follow. How did the co-worker discriminate against the Asian guy?
Now if he did, and said something like - your race is fucking weak, you don’t belong here with us - than yes, that would be racism.
But simply thinking that Asians don't handle alcohol as well as Europeans do, is not racism.
... what? Asians are the same species as every other race. The idea that Asians somehow did not evolve this particular thing has nothing to do with the genetic change over time that causes speciation/evolution. I think you grossly misunderstand evolution and that your remarks are ignorant (and I think many people would claim racist).
Unfortunately your objections make no sense. It's well established that some human subgroups have different physical adaptations (eg. lactase production) that have been naturally selected in the presence of local food sources or production methods. How is that unrelated to evolution?
Example: When exposed to the sun, white people have a higher risk to get a skin cancer than black people (especially if they live in Australia). On the other hand, black people having a skin that filter more UV and make them more vulnerable to a Vitamin D deficiency (especially if they live in NYC).
This is simply because they evolved to adapt to different climates. Just claiming "no, there is no difference because we're all the same species" is plain wrong.
I think you're the one proving ignorant here.