There's nothing wrong with isekai, and originality isn't necessary to make a story good.
The issue is there are a lot of bad authors. I guess you could argue there is too much demand for isekai, but not enough competent authors to write them.
MC is trash anyway, so I don't know why he's complaining. He let bandits go after defeating them, even healing them back up. I wonder how many people those bandits have killed and will kill.