Because as always it's always about getting somebody else to pay for everything.
We have this perception that the rich are just there for the taking and they're going to accept being taxed for every single penny they have but they won't. They're more than capable of leaving the UK and they will.
You've said that you're not arsed about rich pensioners but 1 in 4 of them are millionaires and they all get money that they shouldn't be getting.
They're not even getting rid of the winter payments, if a pensioner is poor then they'll still get it so what's the problem?