The tree was probably likely diseased. I'm in South Orange and about 2 years ago 3 trees on our sidewalk area (we're on a corner) were removed because of some sort of disease.

We do have plenty of oak trees in our yard that are huge and might be diseased that we'll have to someday remove.

From what I've seen based on local discussions in Facebook towns are generally only removing trees for good reason, but they're never properly communicating that reason.