Since we are off on tangent anyways....I disagree with the "going for the ball whole time". The intent of the charging player wasn't to win the ball. The intent was very clearly to push the other player off the ball which is why the force was more than what was necessary to just gain possession. Indeed, the charging player falls to the ground (which you might ascribe to a lack of balance because of the cast but that's just a case for not playing with the cast). There was no attempt to actually play the ball and the force used was more excessive than necessary.
That's not the end of the inquiry, though. The next question is given the guidance's missive to reduce intrusions into the game, whether the game should be stopped for what is very clearly and technically a foul. After all, how many times have we seen shielding attempts to let a ball roll out of bounds even though that is also technically the foul of impeding with no attempt to play the ball. Part of the problem is also the relative size differences of the two players and the particular age and body control in their development. So if it's the pros in the EPL no foul, play on...two 15 year old top flight players (where by this point each is likely the same relative size) play on (if the game is getting out of hand and needs to be pulled back or the contact is becoming excessive enough that someone might get hurt, maybe whistle)...kids this young, also being mindful of the need to control the game, whistle no card.