We detached this subthread from https://news.ycombinator.com/item?id=13624340 and marked it off-topic.

It's actually not derogatory: "A dark horse is a little-known person or thing that emerges to prominence, especially in a competition of some sort, or a contestant that seems unlikely to succeed."

https://en.wikipedia.org/wiki/Dark_horse

"Dark horse" isn't a slur or pejorative in general. It's roughly equivalent to "long shot" or "underdog" or something like that.

Per wikipedia: "A dark horse is a little-known person or thing that emerges to prominence, especially in a competition of some sort, or a contestant that seems unlikely to succeed."

In this case I would imagine it's because Red Hat is pretty tiny compared to IBM/Google/Oracle and could not put up a comparable amount of money for the purchase.

Dark Horse is the horse in the race nobody thinks has a chance of winning, but comes out near the front in the final seconds (surprising everybody). You could've just Googled it.

my goodness, this is probably not a native English speaker, or perhaps never heard the expression before... why be so harsh?

Dark horse in this context means other companies unlikely to actually buy it, or win the bidding war. Its not any sort of slur that I'm aware of.

dark horse just means not a main favored candidate