Perhaps because the announcement was already delayed by a week, and something had to be done in the run up to what was massively overhyped as "freedom day"? As it happened, I read the announcement last week as precisely what you suggest - a deferral of the decision for 4 weeks, possibly less, depending upon the data. I do grasp that the restrictions are extremely serious, not least from what I read of the obvious pain that the current situation is causing a number on here, and will be delighted to be able to live normally. But I also grasp the way that this country has simultaneously tried to "protect the economy" and had some of the worst figures worldwide, and draw the conclusion that hoping things will be ok is not a good strategy, and has made things worse - in blood and treasure - than it need have been.
Very simply, I want the restrictions over, and permanently so. I work with colleagues in India; I'd like to be able to go for a drink with them again - here or there. I'd like to see an old friend living in Oz for the first time in years. I'd like my son (year 11) to do his A-Level course in confidence that he'll actually study the whole syllabus, unlike his GCSEs. To do that means case numbers, hospitalisations, and deaths being at low enough levels for the public as a whole to tolerate and not perceive Covid as being an excessive risk to them.
I observe the pattern of data being reported, and agree that it is showing trends that are better than appeared to be the case even a week ago. I also observe that no intelligent commentators are suggesting that we are well below the level of vaccination required to achieve herd immunity, we don't know what effect time will have on individuals' immunity, and the ability of the NHS to "cope" with the two surges in cases has been at enormous cost in terms of both delayed/missed treatments and exhaustion of the highly trained and experienced staff we most rely on to deliver those treatments.
Like you and others, I am frustrated that the "official" modellers have a tendency to make excessively pessimistic assumptions - while also noticing that sensible observers (I find the analyses by James Ward consistently interesting) are also very conscious of the very fine lines between success and failure. Unlike you, though, I believe that these differences and the policies that follow them are based on people acting in good faith, trying to respond to extremely demanding circumstances under massive pressure - not a determination to prolong restrictions.
So, what of my reaction if there are stories about something disrupting progress towards the release of restrictions in July? Given the data that's steadily emerging, I do believe the burden of proof is shifting from "can we justify relaxation" to "can we justify extension". I fully expect there to be a variety of voices, and that those voices will - as ever - consist of a varied mix of self interest, ideologically motivated positioning, and good sense, frequently mixed in the same individual. I also fully expect that there will be voices on here throwing their teddies and threatening all sorts of consequences at any suggestion that we don't get freedom NOW.
But I don't, never have, and never will accept the grotesque views of some that the restrictions are a deliberate strategy to limit our freedoms in the long term, or are not justified in terms of trying to deal with the pandemic as it has actually affected this country, or even that Covid is a real medical problem. There have been mistakes; in March 2020, in the autumn, travel from India are high on that list. But those are questions of competence, not malice.