And?
People were being careful and the concensus of opinion was that we could begin to return to normality.
People are no longer being careful so advice changes. We have to limit economic damage as best we can.
Sorry but you're rewriting history there. That was not the consensus of opinion in July.
The Chief Medical Officer said in July that the UK had reached its limit on how much more could be opened up if the virus was to be kept under control. The government responded by spending all of August telling us that we all ought to needlessly go back to the office even if we could do our jobs perfectly well at home. That was clearly over and above what Whitty was saying we could afford to do. Especially with us needing to keep the decks clear in order to make way for schools to reopen.
Scientists have repeatedly warned us that we were a long way off any kind of return to normality. So it's entirely correct to criticise the government for having to change its messaging