Jon McGlocklin is absolutely right

If you watch local television broadcasts or cablecasts of Bucks games, you are forever hearing Bucks legend and TV color commentator Jon McGlocklin implore the team's defenders to "stay home on the jump shooters!" or "close out... you've got to close out on shooters!" He repeats these imperatives so often, he has taken to apologizing for it. He shouldn't. It turns out he's exactly right.

According to statistics compiled by 82games.com, the Bucks allow their opponents to shoot the highest "eFG% on jump shots" allowed by any team in the Association. Their perimeter defense is so bad, in fact, that no other team is close to being as generous on jump shots as the Bucks. The Bucks are allowing opponents a 47.7% eFG on jump shots. Only three other teams allow a jump shot eFG of even 45%! Something is very wrong here. Why are the Bucks so deficient in this area?

Simple-- teams are breaking the Bucks down using the pass. It turns out Bucks opponents have a higher "assisted jump shot" percentage than the opponents of any other team... again by a wide margin.

What does this imply? One, that the Bucks perimeter defenders are consistently overreacting to penetration. They are too often getting sucked too far in by penetrators to effectively challenge jump shooters when the penetrator "kicks out" to them. They need to stay at home and trust their interior defenders. Second, it implies that the Bucks perimeter rotations are frequently too slow or else nonexistent. When the ball is on the opposite side of the court, the defender is taught to "suck in" to the lane. However, he must still maintain ball awareness, and must hustle back out to his man if the ball gets swung back to the center of the court. The Bucks are not doing this quickly enough or well enough. Thus, teams know that if they simply reverse the ball against the Bucks, they will find wide open jump shot opportunities.

These defensive malfunctions are symptoms of bad coaching. A good coach would have recognized such obvious and continuing breakdowns and would have taken the steps necessary to correct them long ago. If only the Bucks had a good coach.