I hear you that it's normal for you. It's not normal for at least 90% of the population, though.
Cambridge dictionary definition of 'norm': an accepted standard or a way of behaving or doing things that most people agreewith:
As I said before, it is not a cultural norm in the UK to mix with strangers in the nude. The stats you quote back that up, even if taken on face value. Yet having looked into them some more, the 6.75 million quoted relies on a very broad definition which is much wider than just people who frequent nudist events. It includes anyone who's ever sunbathed naked once, or has gone skinny dipping once. Whereas if you look at the membership number for British Naturism it's around 10,000 only.
You seem to be getting annoyed that I'm pointing out that what you like to do isn't the norm. But it isn't the norm.
Around 8% of people commute to and from work by bus. Would you describe them as “not normal” or as a “fringe sub-culture”? And if not, why not?
This is just silly, and not analogous. While lots of people will travel to work by other means, it isn't seen as unusual to travel by bus, and it doesn't transgress a taboo.
Where I live is on any “normal” road in any “normal” town, and yes, there are people that sunbathe naked in their gardens during this heatwave.
Come on, you're talking about yourself here, aren't you!