Somewhere on a youth baseball field right now, a coach is telling a 14-year-old to stay away from the squat rack. "Lifting will make you slow and bulky."
That advice didn't make sense forty years ago, but every year it gets repeated is a year another kid leaves real velocity on the table because of a myth nobody bothered to update.
Here's the direct version: lifting doesn't make you slow. Bad programming makes you slow. Those are two completely different problems, and mixing them up is costing frustrated players the exact thing they're chasing — bat speed, throwing velocity, sprint speed.