This is not a spat it is a debate about the latest moves in a situation that has been ongoing since the end of WW2. It is about the relationship between London's airports and those in the regions. Manchester is the focus because for seventy years it has done more to highlight the inequalities and has more to lose than any other.
This may not be a truly United Kingdom and it certainly isn't when it comes down to investment in major projects, in the way governments of all complexions have put their weight and often funds behind projects and in the promotion of inward tourism.
In terms of aviation policy, the UK has always been focussed on London. There is the argument that this is a small country with the need for just one gateway.
If this was Ireland, with the major concentration of population and business around the capital, that argument would stand up. In the UK it doesn't. There are distinct large population and business clusters each with its own claim to a need for a range of direct services.
Check the population statistics and the number of businesses for a seventy mile radius of LHR and MAN and then explain why Heathrow should continue to have such a heavily weighted bias in its favour to the detriment of everywhere else.
As the gateway airport to the capital it must have whatever service it can support but that should not be to the detriment of the regions which have their own needs.