All of you guys talking about first girl winning when she isn't even in the race.
The way I see it, this is one of the few manga, that might actually go true harem. He's like the only guy around.
In their society where women can eat peaches and gain super powers, women are technically physically stronger usually. Most men are intimated by the Mato squad because they don't want to be with super strong girls, and that's the reason why the Mato organization has so few males.
The protagonist is in a unique position where he's a guy surrounded by girls who are risking their lives but have an abysmal romantic outlook. He doesn't care that the girls might be physically stronger, he just wants to participate in helping other people survive the supernatural disasters that can fall on people.
Shu, and Tenka are super forward with him for that reason. If the story goes in the same direction it's been going in, it's probably gonna go the harem route.