To be fair, they didn’t know he genuinely had feelings for him. They thought he was scared to tell him out of fear of what Sawa would do, so they decided to tell him and take all the blame so Sawa wouldn’t be mad at Ryu but instead at them. I think they genuinely thought they were doing the right thing.
No, it’s the fact they saw his reaction 2 times and they clearly seemed shocked. They told their friend who they assumed was straight to tell the truth in TWO separate situations and he urgently said he couldn’t each time of course they’ll think he’s too scared to say it so they did it for him. They also didn’t know he was in the house. They still see him as sort of scary, the story even said the uke is the only one who knows he’s actually soft hearted so they were trying to help. It’s not their fault that the uke was literally playing both sides. In a prank situation to the twins and in a loving relationship with Sawa. This whole misunderstanding started and ended because he refused to tell the truth.
But why did the twins had to say it , like they genuinely thought they hooked up just to pretend the confession was real ? They can’t be THAT dumb right ?