Even if we agree that he was offside (and I genuinely didn't see if he was or not from the briefest of replays once UEFA made their minds up 5 minutes later that it was offside) - the ref signalled for a foul, so mechanically the goal was wrongly disallowed.
In that it was disallowed in an incorrect way. Which is pretty piss poor officiating.
It's a lot more okay because it indicates his intentions are more likely to boost his local team of which he was presumable a lifelong fan.
It's a far cry from Abramovich using Chelsea to shore up his political and personal security, or the UAE using Man City as a sportswashing vessel to for PR gain for their theocratic police state.
I'm not pissed about teams with rich backers spending more money. I'm pissed about what interests are being furthered by football clubs being used as cynical political tools.