[KirinDave]

> As in, OP feels going to the conference is a must, "a given", a "constitutional right", and that the manager "wronged" him by not letting him go.

Well, free assembly and association are in fact corrolary to "free speech."

If an employee wants to go speak at a conference and the manager says, "Don't" then one of two things are happening:

0. The employer is abusive and undeserving.

1. The manager is attempting to take credit for the employee's work and should be called out.

There really aren't other scenarios; there's no valid reason to attempt to sabotage someone's career arc.

> OP focuses on himself, on what he wants. There is no mention in the question of what the manager wants. It screams "me me me"

Well evidently the manager in question isn't going to help the OP with their career, so someone's gotta do that. When a company aligns its interests with the career growth of their employees, then its a win-win. If it's pitched as an adversarial relationship, then there will be a winner and a loser. I cannot imagine why a good manager or intelligently run company would encourage such an adversarial relationship; it'll cause massive turnover.