Physical good look is only one factor that goes towards someone's attractiveness. Being physically good-looking will help your attractiveness quotient, but you don't need to be extraordinary. There are many instances where a person is 10/10 on my scale of good-looking, but I feel very meh! about them. I can enjoy looking at them but have no desire to watch them long-term or find out anything else about them. And then some people are decided "average", but I find them utterly compelling and sexy. With actors, it's usually from the role that they play and their ability to capture that character.
I don't know if any of you ladies here have watched Kdrama, Heartless City. The lead actor Jung Kyung Ho's look is not my "ideal", but as Baksa (the main character in Heartless City) he was hot. Subsequent works cemented his talent to me and while I never found him as sexy as Baksa again (Baksa is just sexy, OK :-)), I watch his shows and think he's attractive in his own way. Whereas Lee Min Ho, does absolutely nothing for me.
We all have different tastes and as long as we are not being cruel to people over things that they have no control over (it's genetic, there's not much that they could do) politely expressing our preferences and opinions are fine. Just don't go onto their social media page or tag them in your comments about how they don't meet your standards. That's crazy behaviour.