The biggest problem is people commenting on the rules without ever reading the rule. (That includes Brandel Chamblee, and it's not his first time misrepresenting the rules.) The rule clearly states that it is directed at the intent to influence another player. As Charlie observes, these elite players are so tuned into their equipment, shaft flex, carry distance, ball flight, ability to change ball flight, etc., that having the knowledge of what another guy hits is of no benefit. And apparently the practice is ignored on the tour level, probably for that reason. It would be unfair to all of sudden start enforcing now just because we saw it on tv.
Why the caddies do it is unknown to me. You have to factor in that most caddies are idiots, and these idiots shouldn't cost a player.
Also, most people seem to feel the penalty is only on Koepka, but it's a stretch to think he just all of a sudden offered this wisdom up unsolicited.
The caddies are sharing information. It's useless. It's stupid. No one is influenced by any of it, and nobody cares.