Fed Balk ruling

[Benchcoach]

Originally Posted by rbmartin

"I guess he felt the movement constituted some sort of feint or something.

You initial guess was correct.
6-2-4(a) Says, "Any (my emphasis) feinting toward the batter..."

I do agree it is a judgment call and understand that it is one you would not make. But the term ANY makes it difficult to argue with the umpire exercising his discretion.