exactly... in this case it’s all a matter of point of view, the “standard” for the MC is far beyond common sense for existing beings in this world, even though he’s OP he “still” doesn’t understand very well about isekai travel and about common sense, that was the reason he was alone in that place testing spells (abandoned by those who couldnt stand his lack of common sense)
I mean the “trick” he showed is much more complex than it looks and takes thousands of years to complete and he did it in seconds, they just don’t have the know-how it’s produced and they didn’t understand what he tried to show and they judged him useless for their ambition
It’s not like he has to show an anti-life equation magic just to prove he’s not useless to people who took him out of the world he was in for their own benefit and then discard him for not meeting their expectations