I agree with your first sentence, but the rest makes no sense. It's under Googles control, not Apples. What does Yahoo or Bing bring up? More importantly, what does Siri bring up in the area where Apple doesn't own the trade mark? If Siri only directs to Apples watch page then it could be an issue for Apple.
For your bidding war thought, just imagine... "Siri, find Fritos." "Sure, here is the Apple Watch". "Siri, find Rolex". "Sure, here is he Apple watch". That whole idea could get out of hand quick. Now, asking Siri for iWatch in a location where there is a trademark for it and getting a link to the Apple Watch, they would certainly have a case. Not so much with Google.