Seriously did not expect this thread to turn out out like this.
All right, for starters, there is no goddamned tracker. Seira is a little yan right now, but believe me, her feelings are genuine. This little yan spike is going to hurt, but also lead to great character development. Of the five girls, she is the most admirable for how hard she tries.
Second, yes, he's naive.
THERE IS NOTHING WRONG WITH THAT. There are people as naive as he is in our world. Other men as naive as him exist in the 1:5 world, too, born there, raised there, and still believing in the fundamental kindness of women. They end up far more traumatized than Masato when their naivete is shattered. Just because we as readers have omniscient third person perspective does not mean a character acting on his own conclusions is a moron. Naivete is not a crime. Nor is his complacency in being lulled into thinking he would be fine when the world was so similar to his own. He's a genuinely nice man who lacks malice.
Third, there is no reason for there to be more lesbians in this world as a percentage of population than our world. The ratio between the sexes changed, but everything else is consistent with our world to the point Masato is seen as a nice, naive lad. Since study after study has shown that LGT is around 3.5% of the total population in our world, we can estimate it to be lower in this one since there are fewer men. That also means that 1 out of 100 men are gay, which means the 1:5 world is even worse for them than it is for women.
Fourth, polygamy is not accepted legally, but women are pushing for it. We see men in this manga with multiple women, so there are women who will accept an illegally polygamous relationship just to get access to a man. We also see that many of those men are douchebags. Genuinely nice lads like Masato are rare enough to qualified as endangered species protection.
The manga is doing a good job of adapting the light novel, so I recommend folks go read it. Especially since the illustration for this scene at the end of volume 2 is so much better there.