What do you expect to gain in doing this?? They don’t need to be told this, and telling them this is bullying. Are you actually trying to hurt them emotionally?? Because telling them this is just cruel. You’re obviously a lot taller than those you’re telling this to, and telling shorter men/guys that they “won’t have a chance” with the opposite sex all over their height is just despicable
“Important to be” is the wrong language, but it’s absolutely fine if someone doesn’t find someone else attractive because of their height, color, or anything else. Attraction is subjective.