This is a classic case of reshaping what people are saying then arguing against the new thing you basically made up.
No one accuses Mourinho of hating kids or never playing teenagers, so trying to concoct proof against that claim is meaningless. It's like trying to prove Ozil isn't lazy because he runs about in games, the media reframed the criticism that he was lazy and then when on and on to 'prove' that false. The problem was the complaints were he was a giant girl and didn't show up in the big games, not that he didn't run around a lot over a whole season.
Mourinho doesn't like to give young players who are unproven a chance, this is fact and it's seeable at every club he's been at. It was a monumental mistake to push KDB out and favour the likes of Oscar, but Oscar was known and proven in terms of he knew what the player could do and was happy with that, KDB needed games to get form and confidence and Mourinho had no idea how he'd play after 5 games so never risked it. This is what he's accused of.
Playing Rashford who was an established member of the team isn't the same as playing Rashford having not played much if at all for Utd. Likewise playing a kid because everyone else is injured is NOT the same as trusting and bringing through that player normally. Likewise playing kids because you've quite publicly given up on the league to focus on the Europa cup and don't want to risk players is again not the same as intentionally choosing to bring a young player through and actively wanting to give them a chance to prove themselves.
Average age of the squad means nothing, because he didn't put the squad together, minutes played by teenagers is irrelevant for the same above reasons, he gave up on the league, he wasn't giving those guys a run of 5 games midseason, but at the end when he literally abandoned the league and was saving his squad. No one I've ever seen has said he won't buy younger players either if a 20year old looks fantastic already there would be no reason to not buy him. But Mourinho absolutely has a habit of buying experienced players who are at the level required and not wanting to buy guys who look like they need building up into the quality of player they look like they can be, more so than the majority of other managers. He builds for instant impact and at multiple clubs this has had an effect on longevity of his squads competitiveness.
