I think the "optimism narrative" comes from the same source as "take back control" growstuff. The aim seems to be to paint anyone who isn't "us" (pro leave with no sense of compromise) as doing down the country. Surprise, surprise, it taken life on GN too. Very nasty propaganda but, it has been through history, sadly.
It seems even worse that the very same people taken in by this deliberate and systematic attempt to shape the perception of one half of the country in order to achieve achieve power for a small cabal are having a go at those who "other" Jews (which is of course, also wrong). What they cannot seem to see is they are behaving in the same way and that their behaviour is unacceptable for the same reasons.