If Lena suggested that Holly get friendly with Robert or Mike then I'm sure you would all think it was odd. The fact that you view Stan as a geek is what makes it seem normal I guess.I'm aware of the belief that a man and a woman can never be friends, but that isn't applicable to every relationship. Especially if at least one of the two parties isn't interested. Stan and Holly geek it out, they can spend hours talking without considering a relationship.
Not that I disagree that Stan likely forms a crush pretty quickly on her. Then she will reject him, if she is taken.
Imagine choosing Stan over Ian.