Honestly I don’t get why this is such a big deal... we already knew what kind of shallow relationships Toudou had before Kirishima. This was just a logical extension of that.
You’re right he was a dick but we ALREADY KNEW THAT.
To him it's an embarrassing past for him. Sure, Kirishima wouldn't mind but it's still embarrassing.
Honestly I don’t get why this is such a big deal... we already knew what kind of shallow relationships Toudou had before Kirishima. This was just a logical extension of that.