Thing is Joey, the fact that it is news is testament to the fact that Nissan needed reassurances following the vote. That, in a nutshell, is what you seem to not recognise. The Out vote created uncertainty, which leads to fear and worry.
Lob in the "ability" of politicians to sort the uncertainty out, and that is why, welcome though the Nissan news is, it will need to be replicated, time and time and time again. Not just with companies in the UK, but pretty much every single export market that we give a fig about.
So labelling folk who do not share your Tally Ho (!) approach to the future, can get a tad irritating.
The future is uncertain. It may be ace, it may not be, but a huge amount of work needs to be concluded before any bunting needs unfurling.