Of course that's what really happened. But do you think anyone would state that IC? :PHe wasn't kidnapped, he attacked them, and was taken prisoner for it, and made to pay a price for it. No one targeted him, HE targeted them.
Or maybe their character just wasn't stupid, made a good guess, and then the guess happened to be confirmed later. It's not metagaming to be a slaver, get kidnapped, guess it was likely to be the Promenade, and then be correct. It's not that player's fault that it wasn't as clever as you folks thought it was.
It had nothing to do with the promenade as a faction. It was a random attempt at murder on his part that didn't go his way.
How do you know this? It's a hell of an assumption. Maybe... someone sold you out. Do you really know?
Maybe someone was followed back to the Promenade? Or maybe the character was just a suspicious, murderous bastard? Does it really matter? We're all grownups here.
There's any number of things that could happen that leads one character to believe (even if they're wrong or were lied to) that one character is part of a certain faction. To claim it was "metagaming" is a big assumption, frankly. You don't have all the facts. Neither do I.