You're not alone in being angry - already there's quite a bit of muttering going on in various places. On reflection I'm prepared to concede that the highlighting in the preamble is one logical solution to the instruction therein; it's also a novel idea and the Listener's all about innovation, BUT:
It's hardly surprising that so many solvers dismissed the appearance of HARE in the preamble as a coincidence and an unlikely solution, not least because of grid sending issues. No doubt the feeling of "there must be something more than this" was strengthened by so many red herrings in the grid, such as SEARCH AREA in the grid and several near-appearances of HARE and other thematic stuff. I always thought that one of the requirements of the Listener is that there should be no doubt about the endgame, as there obviously was here. I am surprised that the editors didn't suggest putting something in that somehow confirmed the preamble highlighting, as it was so unusual. Sadly for Poat, an otherwise excellent puzzle has turned sour for a much higher number of solvers than average.
I always laugh when people say "it's always in the last place you look" - well of course it is as you don't carry on looking for something once you've found it, right? Here, though, many of us have done just that.
OK, I've said my bit and I'll shut up now.