I would think "not capable of producing a net-positive yield" a pretty compelling reason. The field has been researched for more than half a century and yet to date we still have zero evidence this is even achievable. The limiting factor always comes down to sustaining the pressures and temperatures required to get the reaction to occur. Color me cynical, but I just don't see it. Perhaps you could provide some actual experimental results which support your specious allusions to my misunderstanding of the current state of the art?
It's not a reason, it's just your assertion. You didn't back it up. There is no physical reason to believe your assertion is true.
Consider that someone could have (and many did) make the same argument about reusable launch vehicles. Then SpaceX put an end to that.
You need to burrow more deeply to get to the real objections. They have to do with details of economics and engineering. Your facile approach doesn't cut it.
Sorry, the onus here is on you to provide a single shred of evidence to support the dubious claim that the technology is merely hindered by "details of economics and engineering". Fact: fusion reactions are not self-sustaining. Fact: we have never even come close to break-even. Fact: fusion research is a huge industry which attracts BILLIONS of dollars of funding every year (and hence there is little, if any, motivation for researchers to stop proselytizing fusion power). Your turn...
