If you watch the clip it can really be taken as a joke or a real coming out. 50/50.
If it was a joke people will be upset with him for not taking the coming out process queer people go through seriously, people will also be upset that he felt the need to say he was coming out just to justify saying Harry Styles is hot, because apparently straight guys can't say another guy is hot without it being gay.
It seems like him saying "he's hot" slipped out, he lets out a noise immediately afterwards sounding like a sigh of regret, he then seems to try and cover and deflect by saying "he's charming too... a lot of things", he then appears to accept defeat, umms for a moment and reluctantly says "i guess this is my coming out video".
But the video is pre-recorded and edited, so it was deliberately left in, i would like to think if he felt uncomfortable saying it he would have requested for that part to be cut out? So if it slipped out why did they leave it in the video? Unless he had no control over the interview, and if he asked for it to be removed and they declined just to get the scoop that's a really shitty thing to do.