It was and is a speculative technology, but what is the harm in reallocating funding from say, fossil fuel subsidies, into fusion R&D? Even as a purely scientific endeavor, who knows what kinds of useful knowledge and applicable by-products might be found along the way. If fusion is such a dead end, why have there actually been new discoveries made over the past several years, even if they might be hyped? Do you believe MIT/CFS, TAE, JET, or ASIPP are just burning money or something? Who are you to claim that a technology is impossible? Skepticism in fission does not have to convert to the dismissal of fusion.
I also do not back orbital, beamed solar power. That, too, could work. But it, also, would cost more.
Things that cost more displace less CO2 emission, per dollar spent. We have a need to maximize displacing CO2 emission.
So, money spent on fusion is welfare for the military contractors who build the test articles, and for hot-neutron physicists who might be needed for weapons work.
It is good that a few plasma fluid dynamics physicists and their grad students get the odd bone or two, because it is a too-neglected field. It would be better to give them the whole budget.