Maybe it's just confirmation bias on my part, but it just seems like these kinds of shows are more likely to actively receive bad reviews than be ignored, which is what happens to most of the stuff that I would judge as truly bad. Compare, for instance, Hell Mode, an utterly cliched isekai that's also currently running and which I would say was more deserving of bad reviews, because its creator wouldn't recognize an original idea if it bit them—not one word's been said about it. Even Beheneko, which was an unapologetic brainless boobfest held together by a thin surface skin of plot, didn't draw as many bad reviews here as Sentenced to be a Hero.

Upon reflection, the answer might simply be that the people who are giving this one bad reviews watch a lot less trash than I do and therefore have a differently calibrated evaluation scale.