This is funny since most icy veins guides actually tell you to pick whatever the frick you want.
Jokes aside there were points in the game where racials made more up then just 1-3% of your damage or had otherwise massive influence (goblin jump on KJ).
Now most people thought like you and so did I, however the top end players naturally gravitated towards the stronger racials since they would sell their mother for a small edge in world first raiding.
And this of course had a trickle down effect so if you want to mythic raid even in an average guild i strongly advise anyone to either go horde or pick a very healthy alliance server, just to be safe in the future because this ain't getting better.
If you don't raid or only want to do heroic max? yeah whatever pick what you like.