4 weeks in so many people are just saying, oh well, too bad, sick and old just stay at home and suck it up...
What actually is the alternative, though? For everyone to stay at home for years in the hope that one day a vaccine or a cure is found? I don't think the lockdown should be lifted yet, but at some point it will have to be, unless you think the government has an endless stash of money to pay more and more people not to work as their employers' businesses collapse, while continuing to fund the NHS and benefits and schools and police and all the other things it already pays for. And the chances are that the virus won't be completely gone by the time the restrictions are lifted, so at that point - whenever it is - people will have to start making their own decisions about whether they want to risk going out, based on their personal circumstances.
By the way, I actually think that this was one of the strongest arguments in favour of the herd immunity approach. It was painted as the government not caring about vulnerable people, but telling anyone at risk to stay home for, say, three months while the virus rages through the healthy population and burns itself out is feasible. Saying elderly and vulnerable people should stay home for years while the virus continues to rumble along slowly is obviously not, so most of those people are at some point going to have to leave the house while the virus is still circulating and put themselves at risk. Herd immunity may well have been the best option (besides containment) for those who are shielding, it just would have been a potential disaster for everyone else if the hospitals couldn't treat everyone who needed it.
In addition, anyone shielding who is currently receiving furlough pay or other government assistance while they're unable to be in work is far more likely to receive it for longer if the government isn't also having to pay it to millions of perfectly healthy and very low risk people, who would in all likelihood be fine if they went back to work but currently can't because of the lockdown. People in the lowest risk categories who have been furloughed or made redundant will NEED to go back into employment in the short to medium term, to take some of the strain off the economy so that higher risk people who can't WFH can continue to receive financial support.
We're nearly six weeks in by the way, not four.