No, varessa has absolutely no reason to hate blood elves (other than fact that she is traitor), and entire high elf "high ground" over blood elves makes just as much anti-vaccers policies. Poor innocent mana wyrms. Its so inhumane to feed from there. Btw, one more steak for me please.
Arthas was a human prince, who was raised (poorly) by humans, tutored (poorly) by humans, and not contained by humans. Than as human decided to commit genocide of as many elves as possible because they pissed him off.
The key diffrence betwen garithos and garrosh is that garrosh was opposed by vast majority of horde, who stood arm to arm with blood elves against him. Garithos was opposed by...oh right. Noone. Elves were left to themselves. And saved by neutral party.
Oh and then garithos was killed by...guess who ? Sylvanas ! So thats one more point for red team.
Oh and actually orcs did fought their corrupted counter parts, there is even W3 mission about it. On top of that unlike alliance who send you know, spies, saboteurs and murderers, orcs, trolls and forsaken send this weird thing called "diplomats" (you can even see them in silvermoon !) and forsaken even send reinforcements to ghostlands to help them deal with scourge remnants and number one traitor (who isnt windrunner sister).