Only to criticism of the form "X can never ...", and some such criticism richly deserves to be ignored.
(Sometimes that sort of criticism is spot on. If someone says they've got a brilliant new design for a perpetual motion machine, go ahead and tell them it'll never work. But in the general case it's overconfident.)
And with fusion, we already have a working prototype (the Sun). And if we could just scale our tech up enough, maybe we’d have usable fusion.