Again yes it's a special accomplishment for him to score his at that age but it doesn't earn the club anything extra does it? Do we get more points for a player defying his age?
If he'd been at the club for some time, now an ageing asset, I don't think anyone would've have been anything but highly impressed and positive, etc.
The problem is that he was brought in, at his age, as part of what Mourinho himself apparently regards as a gradual rebuild process. He doesn't make 100% sense in that context. He clearly wasn't brought in as a grand old backup option with the added benefit of functioning as a mentor figure – but as our main attacking weapon.
When we went for him, my initial thought was that Jose considered the rest of the team strong enough to be there or thereabouts – with Zlatan added as a ready-made, if old, killer to win us crucial points. Sort of like Fergie's RVP move: Nevermind the overall, long-term picture, just add some sheer attacking prowess to make the difference because the latter is available and will work out short-term.