I think that doing the “neighborly” thing is the right thing to do. Whether that means buying a chainsaw (or renting one; no reason to buy one if you don’t have the need), doing the work yourself, calling in a company to do it, whatever… it’s just what you do–like you went and helped your neighbor jump their car. Especially if it’s something that came from your yard. Whether it’s technically your responsibility or not, you have an obligation (unless you plan on moving soon, or don’t care about possibly making your life hell via your neighbors’ new dislike toward you), to clear the tree.
OP didn’t have to get a chainsaw. OP could have, maybe, hooked a tie strap up to a vehicle and pulled the tree to be parallel with the roadway, and left the tree as-is for the town (or whatever) to clean up. There are so many possible solutions to this problem.
I think my biggest issue with the OP’s post is the attitude they had. Sitting back and drinking cocoa, knowing your neighbors can’t get to work, to the hospital, to the store, etc. is pretty F’ed up, IMO. Especially if you have the means to do something about it. That’s utter laziness out of spite. “Because I can” isn’t an acceptable attitude toward life, in my opinion. I don’t have time for people like that.
…and I say all of that as someone who isn’t the nicest person around. I don’t go white knighting around town at all. But if this were me, and it was my tree blocking an entire community of people, I’d probably do something about it if the town couldn’t get here the same day to fix the problem. That’s called being a normal human being and not some entitled jerkoff who wants to sit back and drink cocoa, while others suffer. That type of person is a waste of fresh air.