My feeling is like that of astrojams', though I wouldn't like to say what particular part of your upbringing or culture leads you to have such a (to me) weird desire to praise the mundane and unremarkable.
By your own observation, Alex succumbed to social pressure to overcome his fear of heights. He topped off the event with some damage-limiting self-deprecation. All of that's normal. It wasn't especially brave or ingenious or anything. Maybe now he's made the jump he'll be less worried about it next time. Maybe he won't.
Frankly, if you'd gone over and congratulated him, you'd either have embarrassed him (because his dive was so terrible that some well-meaning weirdo felt the need to encourage him) or weirded him out (because seriously, who goes around complimenting strangers?). In the meantime, you're lying (it's not like his dive was actually impressive) and fostering an environment where people get praised for every meagre personal triumph. Please don't do that.
I've responded to astrojams' comment already, but I'd guess his fear/concern about his first jump from the 1 meter diving board is about on a par with my fear of diving from the 3 meter board (something I've yet to do).
If, when I eventually do dive from the 3 meter and join the queue to go again, someone turns round and gives me a high-five, I don't think I would be particularly weirded out or embarrassed. And I don't think it would stop me from seeking my full potential in the future because my meagre personal triumph had been rewarded in some small way.
But hey, maybe I am just weird and sheltered. shrugs
By your own observation, Alex succumbed to social pressure to overcome his fear of heights. He topped off the event with some damage-limiting self-deprecation. All of that's normal. It wasn't especially brave or ingenious or anything. Maybe now he's made the jump he'll be less worried about it next time. Maybe he won't.
Frankly, if you'd gone over and congratulated him, you'd either have embarrassed him (because his dive was so terrible that some well-meaning weirdo felt the need to encourage him) or weirded him out (because seriously, who goes around complimenting strangers?). In the meantime, you're lying (it's not like his dive was actually impressive) and fostering an environment where people get praised for every meagre personal triumph. Please don't do that.