
It wasn’t his intention to out Makoto anyway; it was a large lecture hall, and Shiro stands out so people were eavesdropping even though they normally wouldn’t. His ignorance in that moment makes him unlikeable, yes, but not a bad person.
Also to call what he did “manipulation” feels like an exaggeration, to me Makoto twisted his words only because he was scared. Nagizaka even brought Makoto to a secluded area and confronted him about it but in the end it was Makoto who gave himself away. He even tried to make amends after that. I mean, can’t say Nagizaka is the epitome of an angel or anything but I feel it’s a stretch to call him “a piece of shit” just from this.

Pushing someone to come out is manipulation at it's finest. If you are straight, you wouldn’t know what it feels like to come out. He is a pos for doing what he did. It doesn't matter what his intentions were, outing is a big deal. If he ended up saying what he wanted, that would have been a disaster.
They acted like nagizaka was a bad guy but I feel like he didn’t do anything wrong but try to be a good friend?? Besides him ending up brutally alone loved the manga :p