It's intentional that the MC is an apathetic asshole. It actually seems to be a fairly popular narrative for games in this style to have on this site.
Basically its MC is an ass, dating all the girls at once and is somehow involved in some weird cosmic shit. This plot structure is practically guaranteed if the game's an activity choosing VN made in koikatsu.
I've played three games like this including this one and the MCs are all terrible in the same way. They even all look the same so it's like I'm dealing with the same guy over and over again. This MC is the best by far and seems to be becoming less of an ass faster than the others. Trust me they're usually 1000x worse.
I understand your frustration and hope the MC turns around quickly but it's probably gonna be a while before he stops being so annoying.