Viviennemary I really hate to single you out but I'm going to have to.
I don't know quite what the correct rhetorical term is but this linguistic thing (which I think also indicates how you actually think) of 'personalising' the EU is so, so inappropriate.
The EU is not an acquaintance, colleague, family member or friend. The series of trade and political negotiations that are Brexit is not similar - in quality, quantity or kind - to an interpersonal dispute or transaction.
To try and conceptualise Brexit in terms drawn from the sphere of interpersonal relationships is not simply to 'dumb it down', it is to miss, entirely, what this is about. It is a qualitative misrepresentation which obscures truth.
I've said this before: I understand analogy - it can make complex situations graspable and provide the opportunity for new perspectives on an issue. However, it can also fundamentally obscure reality to the point where the truth is obscured so greatly that it is a whisker's breath from actual falsehood (the 'whisker's breath' of distance lying, I suppose, in the lack of actual intention to deceive).
The EU is not acting out of spite. The EU is an alliance of heterogenous interests, for a start. It is an organisation without unified purpose and intent - particularly in the emotional sphere - other than to produce and operate a common political and economic agenda of mutual self-interest.
If there is a purpose, it is to ensure Brexit doesn't destabilise that agenda of pursuing allied economic and political interests.
Imputing 'spite' renders something very complex into terms so simplistic as to be banal.
My guess is that this notion of 'spite' comes into operation in order to protect people who use this cognitive model from recognising that this is far, far larger than any situation they may have encountered in the domestic sphere of their lives. It also helps to preserve from a recognition that Brexit is disinterestedly damaging for the UK. I notice that it also places the EU in the role of being some kind of unreasonable authority figure, which is the source of harm. Again, I would say this acts to cognitively protect the user of this term from recognition of their own autonomy and actions in bringing about economic and political harm to the UK. Far easier to believe that the EU is some sort of 'cruel adult'.
The EU is negotiating with the UK en bloc. It is a network of interests and groups. Each point in this network are determined upon these negotiations producing the most favourable terms for themselves. 'Spite' has no place in such a complex negotiation. For a start there is no unified 'mind' that could produce such an emotional intention.
I find the urge to trivialise these negotiations into terms more fitting for a local dispute with a neighbour who doesn't look after his fence really quite strange and baffling.