Very well said.
Also, players can change, but once they are labelled, sometimes it is hard to change the fan's perceptions, and maybe being called a "choke" even adds to the pressure..
Josh Beckett was on his way to becoming one of the greatest "money pitchers" in MLB history, then ooops! (He's still got a pretty awesome record, in total.)
David Price was the poster boy for not being a "money pitcher," then ooops!
Barry Bonds.
To me, to many definitive judgements and assumptions are made on tiny and scattered sample sizes, like the playoffs.
It's not that I don't believe some players handle pressure better than others. To me, it seems rather obvious some would likely do that or not do that and some do and some don't, but even this can change as a player learns, grows, experiences or matures.
If someone appears to be a "choke," he may not actually be one due to the randomness of a small sample size.
If the pressure did cause a player to "choke," he may not be one going forward.