The point is respect, something which a lot of people lack these days. The man brought up his daughter for all these years, is it that wrong to ask him a simple question in person?
Actually yes it is, its a tradition and NOTHING more. You bring up respect but the idea is that the father is allowed to control their daughters and tell them who to marry, thats when it first started way back when. So while it might be a sign of respect to the father, is it at all respectful to the woman you want to marry? I'd argue no, not at all.
Likewise, not every father in the world is a good person, not every person out their deserves respect.
Again its a tradition, because the tradition says you ask the father for permission even if he's a drunk abusive rapist convict in jail who doesn't deserve any respect at all.
It might be respectful, but I'm fully of the opinion that people earn respect, showing respect, unearned, means NOTHING. You're asking for the tradition not to show respect, infact you're only respecting the tradition not even the person.
THe idea is archaic, saying that I would ask the father IF that was a great person who I already respected and liked. If I was involved with a woman who I wanted to marry whose father was an a-hole who I didn't like, didn't get on with and was a pratt, I'd feel no need to pretend to respect him and fake the whole thing purely for a tradition.
Just doing it blindly, because everyone else does it and its a tradition, with no care at all into who you're asking and why, makes it worthless and stupid.
It always amazes me how people will blindly do anything without a second thought just because other people do it.
I still wouldn't do what the OP did, if I respected the father already I'd go and see them in person, if I didn't respect the father I wouldn't ask at all, e-mailing was just weird.