For those complaining about the lack of seeking revenge, it might help to take a different perspective:
Possible MC POV (I have not read into it far enough to be sure): The world is a game, everyone in it are tools/toys/game pieces, even the ones who are summoned from Earth. Seeking revenge is part of playing the game, the MC has no interest in playing the game, they just want out and will destroy anything that gets in the way, and ignore the rest, be they bad guys, innocents or even gods.
There are some exceptions of course, but if you consider this as their main drive, many of the MC's otherwise annoying decisions make perfect sense.