I agree that it is a rather shady tactic to force donations from people, when the fact is the queue is completely unnecessary. The Warmane staff should be doing this for the love of the game, not profit. I am actually quite shocked Blizzard hasn't dropped the hammer already, but I'd like to think it's because Private Servers usually aren't out to make a profit. These kind of practices, and the people who say "suck it up or play somewhere else", only serve to make the Admins seem greedy and out for money, and a much larger target for the Blizzard legal team.
Either way, I am sure there is a storm coming, with the recent announcement that Blizzard will be providing free-to-play legacy servers soon..