Sure: don't buy it because of loyalty, that'd be stupid — but not buying it because of some worry about changes that the next version might have (and that Apple has said nothing about and that would be fraught with a number of technical and political difficulties anyway) is cutting off your nose to spite your face. And to use your phrase, it's voting with your dollars against something that's not harmful - if anything, it's sending a message to Apple that a certain group isn't going to buy their freedomful product anyway, so they might as well let those people use Linux/etc and turn the Mac into what you're afraid of.
EDIT: And still is in the corporate market.
The truth is for Apple this might as well be a great business decision. It is probably in their best interests, because their goal at the end of the day is to make as much money as possible. There is nothing wrong with that I just won't be buying it.