Look even though it sounds like Dutch, and is almost spelled like Dutch (and don’t get me wrong, I’m absolutely honored to share these similarities with you), it doesn’t quite have the same ring to it.
People hear: “Oh there goes Dutch”
And they think: “Hmm there’s a cute and interesting nickname, I wonder what the story behind that is, heehee.”
People hear: “Oh, there goes Douche”
They think: “I’m pretty sure I know how he got that moniker, best to avoid him, and treat with contempt.”