Why don't we choose between spending money on coal/war/farm subsidies/health care or fusion? There are more than two options.

The amount of money spent on fusion research sounds large but it's really not that much in the grand scheme of things. And most of it is really being spent on efforts to improve things that have widespread application outside fusion, like material sciences and superconducting. It's really likely that a lot of major advancements will come of this research, in line with the space race advancing technology at an accelerated pace for a while. At least fusion has, from an optimistic perspective, an inherently worthwhile goal besides climbing an absurdly tall virtual mountain to go with it.

Anyways, at the scale of international project budgets, "killing fusion to increase money spent on other green projects" is, at this point, like not buying a daily coffee so you can afford a car.

Even pessimistic estimates of ITER's cost are still under $100B for a 5 decade long project. Or, put another way, less than $2 billion dollars a year. There are highway interchanges that have cost that much. And the EU and the US alone of ITER's contributors have a combined GDP of $35 trillion.