Yeah... I understand his point, but come on, lets be reasonable.
Barkley and Sterling have combined, nearly played double the Full Internationals, than they have U21s (25Full - 13 u21), what will they achieve by doing that? Kane, on the other hand is different, he contributed 5 goals to qualifying, played a bag full of games too.
I think the lads who have been so good in qualifying, and in the pre-euro games, deserve to stay in, and yes that includes Kane, imagine doing such a good job in getting your team to the tournament, only to be told, actually... yeah, you've been brilliant, but we've got a bigger name who wants to play, so you're out. You'd be gutted, so yes, it's about breeding the winning mentality, but it's also about not crushing the hopes of some of the lads.