I think the statement Mourinho giving out to the players in selling Dele is no one is above the club and if you're not putting in 100% then you should not be at Spurs. Hence he was trying his best to tell people that Kane should be MOTM for South Hampton and not Son because of his work rate and contribution.
Selling Serge is different because he could not cross the ball and because he spilled drink on Mourinho's shoes and was caught on camera doing it.
Of all the things to slag Serge off for, his crossing is not one of them.
He was one of the most productive fullbacks one the league in that respect