old man, the point is not to intermingle with goyim. Therefore, their point is not to go to stadiums and intermingle with goyim and follow in their ways. That’s why these Roshei Yeshiva are ridiculing how the game is played to show you how stupid watching the game is. Not necessarily are they ridiculing the actual sport, but they’re ridiculing the fact that you’re watching such a game, watching how the goyim play.
There’s a story about a bochur that missed night seder several nights in a row. His Rosh yeshiva went over to him and asked him why he was missing night seder. He said that the soccer championships were on and he didn’t want to miss it. The Rosh Yeshiva asked him, “Tell me, how do you play soccer?” The bochur answered, “There’s a net and you have to kick the ball into a net.” The Rosh Yeshiva said, That’s easy. I can kick the ball in thousands of times.” The bochur said, “No, Rebbe there’s a goalie who blocks the ball.” The Rosh Yeshiva said, “He’s there 24/7? Wait until he goes home and kick the ball when he leaves and you can win easily.” The bochur said, “No Rebbe, there are obstacles in the game. This is an obstacle and you need to overcome it.” The Rosh Yeshiva answered, “In learning, there are also obstacles, like learning when there’s a soccer championship. The same way you need to overcome the obstacles in sports, you also have to overcome the obstacles in learning.”
(No, the point of that story is not to show you how the goyim play, but you see how Roshei Yeshiva can take sports and make a mussar shmuz out of it.)