Well, without Walt Disney, none of the Disney theme parks around the world would exist. And to be fair, I don’t believe a Walt statue should exist at DL either.
Yes, the quote is directly taken from Disneyland’s opening speech, with Magic Kingdom in the background. Even if Roy did mention the exact words, they are still in reference to DL, suggesting that MK has been living in DL’s shadows since it opened. That shirt doesn’t help.
I think WDW should focus more on the people that actually did contribute to its creation. The reality is Walt Disney wasn’t one of those people. Not directly at least.