The trouble is you are focusing on the immediate personal risks and missing the whole picture
Yes your risk of dying from covid may be small and your risk of needing a cancer appointment may also be low and your risk of having an accident ... all things that become untreatable once hospitals are overrun
Once that happens, you broadband goes down and you can't get it fixed because the engineer died from an untreated heart attack, you can't get your usual weekly shop s the eu have banned all transport to plague island. Your hairdresser is closed because she suffered a mental breakdown when her parents both died. Your job goes because too many people are scared and so don't go back to the pub or gym . Your bin goes uncollected because there are no longer enough bin men because 20% of the workforce are vulnerable
If the nhs buckles , society buckles and we all lose.
We can't "protect the vulnerable " without locking up everyone over 50, taking their kids away from them, refusing them any medical support and sending them all food parcels to keep them out of the shop.