I don't know how ready other mods are to wield their ban hammer, but I try and ban as few people as possible for as short an amount of time possible. The only time I really ban people is 1) for using racial slurs, 2) for making threats or invitations of physical violence, or 3) when they absolutely will not let an issue go and begin to flood the forums with hijack posts regarding it. I use bans as a forced period of cooldown, or to remove a troublesome user (troll, spammer) entirely. I would never ban a user for asking a question like this, even if it's stated in an aggressive manner towards me. But all staff members are different, and handle situations differently.
As far as the reason, the banned user is shown it and the rest of the staff can see it via the moderator control panel. As far as I know, there is no way for a other users to see why somebody was banned. If you have a specific question, feel free to PM me and I'll try to poke around the CP and find out for you.