So you're saying they briefly met a single time? And you expect him to have the man's face memorized?

He probably was introduced to a dozen+ other people before this extended, hours-long hearing.

I doubt he would remember most of them. Dude's only met this guy a single time, and when you meet a bunch of people, unimportant ones like the guy that inappropriately ambushed him just as he was leaving the witness stand probably didn't make much impact.

Besides: If he wanted to shake hands, why didn't he do it when they were introduced?

Why would he do it in an inappropriate ambush just as he was leaving the witness stand, in front of a dozen cameras?

Oh right, for a political stunt.