Oh come on, aside from the TNG episode Code of Honor
I can't think of ANY instance in which Trek has been racist. Trek has always gone above and beyond when showing people of diversity holding respectable and important positions.
In TOS, not only was an important bridge officer black, but also
a woman. That was UNHEARD of. Nichols tells the story of how MLK told her how important her role in Star Trek was, saying that it was the only TV he and his family watched as it showed a future where all sorts of different people could work together. TOS also was the first show to have an on-screen interracial kiss (between Kirk and Uhura).
It's obvious that OP is not serious or is doing this to incite a flame war, as he uses points that actually disprove
his argument to back up his claims.