Mocking the Reflecting Pool is Springtime for Hitler.
Many neonazis and their ilk are okay with their icons being portrayed negatively as long as that negativity takes the form of a powerful and threatening figure. They like identifying themselves with Big Scary Destroyer. It's a power fantasy for them.
That's why, for instance, Trump's incoherence when speaking doesn't bother them. His incoherence is taken, by and large, very seriously. The man opens his mouth and drops a bunch of verbal turds - and the world panics, or at the least gets very, very nervous. Not unjustifiedly, it's true, but the power fantasy of being able to say whatever they want and get taken seriously is still vicariously fulfilled.
But the Reflecting Pool? The Reflecting Pool wasn't supposed to be broken. It's not something Trump destroyed for the sheer pleasure of destruction, which is how Trump's base experienced his gutting of the government via Musk. The Reflecting Pool is something that was supposed to be improved, which he boasted about improving, and instead it's clearly turned to muck. There's no power fantasy there. There's nothing to gloat over; it's just a damp gross failure. It isn't even a catastrophic failure! Tearing down the East Wing of the White House was dramatic, and had the value of making a big, indelible change to a national icon. No matter what happens, the East Wing as we knew it is gone. Power fantasy. By contrast, the Reflecting Pool? It's just fuckin dirty. It's gross. It's your neighbor's neglected cheap pool that's full of dead leaves and slime. An entirely pedestrian, grody, pathetic failure. It would literally be more salvageable as a PR thing for Trump if it got hit by a meteor and turned into a smoking crater.
And that's why we're riding that fucker so hard. This is what's under the power fantasy. Deep down, he's just pathetic. And that's what Mel Brooks understood with Springtime for Hitler. You don't fight the Nazis by making them big bad scary evil guys. You fight the Nazis (when actual weapons aren't a present option) by making them a laughingstock. There is no way to derive a power fantasy from being the object of derision.