Why should that responsibility fall on data centers, specifically?

Because they want to move in and can afford it. Same reason that apartment complexes have to add greenspace or subsidized apartments as a condition of getting a zoning variance.

Maybe not a great example. Municipalities should fund public works projects themselves using sane taxation revenue instead of cryptically taxing private land improvement projects.

Because in a democratic society the people can decide who is responsible for what, that's the price of admission you pay to live in such a society.

That's just what the poster above decided, not "the people" / legislation. Key words "I think" in the comment. Asking that person why they are going after datacenters specifically is a valid question.

There is a "good" answer; data centers are both unpopular and temporarily rolling in cash, making them attractive targets for punitive taxation.

I'm one of those people and I don't understand why we would single out data centers, a largely clean industry, to clean up dirty, industrial areas.

Then get more people to vote with you, it seems like most residents do not agree.

Better do some door knocking to change their minds.