This isn’t what is being proposed at all.
According to the BBC the proposal could be to encourage the elderly and vulnerable to quarantine themselves as much as possible. There has been no talk of locking down the elderly and vulnerable at all.
And tbh, anyone suggesting that is ageist and disablist. Because while you might want to encourage your older and vulnerable friends/relatives to take extra precautions, there’s a difference between that and wanting them banned from parts of the society.
And the derogatory comments about the elderly are still there. About the old people seen in the supermarkets buying only a packet of ham and a couple of bananas, as opposed to the younger people brawling over toilet rolls and baked beans? Who exactly are the selfish ones here?
And how do you forceably lock down the vulnerable who do not fall into the elderly category? Start with the disabled perhaps? We can’t know who is vulnerable in the disabled population so best lock them all down, but then you still have people who are not disabled but who have other health conditions. How do you enforce that?
Whether people like it or not we have to allow individuals to make their own choices without singling out certain sections of society. So while you might encourage your elderly relative to stay home more, it is their choice to do so. It’s their life after all.