Fuck no. People don't get to re-invite themselves to stages they've been disinvited from.
And the original question of how the situation could have been handled better is the most interesting one. The rest is a game of he said/she said, which hn commenters tend to enjoy arguing about but is ultimately not very instructive.
With hindsight it is clear that the situation had been brewing for some time, and the conflict had been escalating slowly. Perhaps due to the pressure and stress (and time pressure) of organising an event like that nobody managed to have enough distance to deescalate it, which culminated in someone being escorted off stage by security, not a good experience for anyone.
Most likely once the invitation to talk had been rescinded the dice were thrown. It would have been hard for the speaker not to be offended, and unfair on him to expect him to take it quietly and move on without reacting. Someone should have been aware of that and worked with him to control the impact of this on his own reputation.
Especially since they were okay with him giving the talk as long as he apologized. And he offered to say “I didn’t mean to offend anyone”.
So for a misunderstanding and mistake to drag him off the stage is stupid and ridiculous.
> What should they have done better? They didn't have the option of doing better with Dmitry, right? He deliberately set up the confrontation with security.
Maybe I misunderstood, I previously read that as “what could they have done better about the situation”.
Did you mean “what could they have done better once he was at the stage?”
The "drag him off the stage" thing was his own arrangement.
They made the software for the badge of your entire conference, for free, and then you won’t let them talk about it because what you got for free, wasn’t what you expected/wanted?
That’s just dumb on so many levels I don’t even know where to begin.
It’s like playing, no, selling someone elses mod and complaining it’s not up to the standards of a finished game.
I think an easter egg that includes a monetary solicitation is (at best) in poor taste, regardless of the circumstances. But canceling his talk 30 minutes prior to its start time for that? Nope, not cool. DEFCON's behavior in disinviting him was much much worse than his action that triggered it.
You are saying this like it is unreasonable, but it seems entirely reasonable to me.
Just because you do something for free does not entitile you to a conference talk about it. If you wanted to be paid for it (and make no mistake, a conference talk is a form of compensation. In many conferences companies pay huge sums of money to have a platform) then they should have got a contract.