Another factor is the extent to which national identity defines each person.
For some it is everything. For TBG it seems it barely registers. I think for most of us it is just one of several/many different factors that make up our sense of ourselves - of who we are.
In my mind it is like a venn diagram of all my tribal affiliations (some inherited, some adopted as a conscious decision). Wales and Cardiff and Cardiff City are big ones, but so are my politics, the city where I live, the music and books and films that have influenced me or that I love, and family and friends.... and possibly other factors too.
I am Welsh but I have more in common with people in Belgium or Argentina or India who share my views and have similar life experiences than with reactionaries and new robber barons who happen to be Welsh and watched the Morcambe and Wise Christmas Special at the same time I did. When we talk about 'we' and 'us' that is not defined by having the same passport cover. There are Welsh people who are not 'us' to me and many people in other parts of the world who are.