It seems so because consuming a gallon of milk a day is a fantastic way to get fat for most people, even athletes.
Bulking is a thing of the past. Lifting heavy with proper nutrition on a small caloric surplus is advocated to pack on lean mass.
I would be happy to be proven wrong, but this doesn't look like a dude who squat, bench and deadlift heavy weights:
View attachment 885991
At 20 years old with his hormonal profile, a couple of months in the gym with a +/- 300-500 calorie surplus should suffice, not downing jugs of milk like a lardass lmao.