Mh, what you did isn't against the rules, but it is generally considered bad manners.

You don't 'need' for things you don't need on the class you're playing right then. If it was any other combination of classes, you wouldn't have been able to do what you did. (i.e. a scholar can't need on dragoon gear, no matter if they need it right now for their other class.) However, because you're a tank rolling on tank gear it's merely sketchy. They look at you and see you obviously don't need that stuff, whether you think you do or not doesn't really matter. It's about perception. They didn't want to run with someone who was just taking gear because he could, which is what it looks like. Everybody can turn gear in for seals or use for desynth. They exercised their right to use the vote-kick system to get rid of a player who they saw as taking advantage.