
um this was cute, then it was ok. I was more concerned and CONFUSED why tanaka (coworker) was the "bad guy" towards the end! Like am i being punked!!? Honestly tanaka's reaction to him finding out they were dating was not the "norm" and keishi said his reaction was "normal". Bro tanaka's reaction was anything BUT the norm. He was super supportive but apologized when keishi corrected him, location could have been a bit better but thats when he put two and two together ya know. He wasnt nervous to be around them or disgusted. He just seemed surprised/happy to find out. And then when he went to apologize again even though keishi was the one that shot him down not their boss about if they were dating he told him to come back and apologize for when he figures out why keishi was upset. Am i just not understanding the problem here??? I am so CONFUSED!!! plus keishi did not handle that well at all!!! JUSTICE FOR TANAKA DAMMIT!!! Can someone enlighten me though?#-.-)

This is kind of brought up in Vol 2. Lemme explain it a bit (no promises that it'll make sense though). SPOILERS AHEAD
In Vol 2, Tanaka's GF breaks up with him. She confesses to him that she actually likes girls. He's (obviously) heartbroken and confused as he vents to Keishi. He doesn't have any prejudice against her being a lesbian, but he couldn't understand she'd gone out with him, kissed him, and said that she liked him. He says it's all 意味不明 (ambiguous/cryptic/incomprehensible), then follows it up with something along the lines with "But, I get why it's incomprehensible [to me]. I don't know anything at all." Meaning, as a straight man, Tanaka doesn't truly understand/know the struggles of those who are part of the LGBTQ community, especially in a heteronormative & conservative society (aka Japan). He then sincerely apologizes to Keishi for what happened in Shinjuku, and Keishi genuinely forgives him this time.
Going back to Vol 1 Ch 2, Keishi says that he's not ashamed of his sexuality, but he doesn't think it's anyone's right to judge him. Which is why he hid his sexuality to the point of acting like he was a playboy. He doesn't want anyone to judge him based on his sexuality. This is the same with his ex-gf, except she forced herself to try to be heterosexual because, again, society.
In my opinion, neither of them saw Tanaka as a "bad guy." Like you said (and Keishi said), it was a typical reaction - albeit kinda overly excited. When he went "...I guess that's hard for someone like you! But you didn't need to be afraid, you know?" in Vol 1 Ch 5, it was like he didn't understand /why/ they hid their sexuality. It doesn't matter if someone is prejudiced or not; it's another's place to involve themselves. They didn't want Tanaka to know about their relationship nor sexuality, so when he was going on about it like "it all makes sense" it kinda feels like their sexuality suddenly turned front-page breaking news to someone who they didn't want to find out. So I think Keishi's being upset at Tanaka mostly came out to how he worded it. Cause, again, what would a straight man know about a gay man's life. Plus, nobody owes anyone a "coming out" just cause you say you're not homophobic, ya'know?
Oh no poor shamu!!! boi u dont deserve to be anybodys second choice!!! That is tragic dude!!! I NEED MORE OF THIS STORY!!!! Fuck u friend!!! Shamu doesn't deserve that!! He deserves happiness like everyone else (╬ ̄皿 ̄)凸