People's reaction to games having multiplayer is so incredibly odd... and dumb. They usually are upset because of their fairly baseless presumption that the developers could've spent all that time used to make the multiplayer mode on the single player instead.
In Infinite's case, it seems like they spent a lot of time trying to incorporate a multiplayer, but it just didn't work out. So, potentially all that same supposed time that could've been used to further improve the main game was still wasted, they just have nothing to show for it. And people are happy? Why? Because you're just bad at multiplayer games and won't have to spend that hour to get the three achievements?
Being bad at it has nothing to do with it. It's worthless and games don't need it out of the few that are so massively successful that nothing else lasts more than a few months. I was never able to figure out why some people need to play deathmatch in every single game when it's exactly the same.