Well I did enjoy reading through this thread although a lot of it was waaaay over my head.
I am a NT volunteer at a country house, not grand but still bigger than your average residence. I volunteer there because I spend time (without paying 😉) in a beautiful place and can meet lots of interesting people who are a) not all middle class b) not all stupid and c) not all there just for the tea and cake.
We know that our place has no obvious/promotable connections to slavery, black lives, LGB or queer stuff (caveat: afaik). We did have a housemaid who went on to be a suffragette, but we don't big her up too much either. There is clear evidence that the domestic, garden and agricultural staff were valued and looked after.
Our visitors hear our stories and either listen or move on. In my years of working there I've not been challenged on the slavery issue or BLM and the word Queer has never been used in 'that' way (also afaik). My fellow volunteers may have slightly different outlooks/experiences but we tend to agree that we choose to volunteer in our place because we love it the way it is, and by and large our visitors do too (they also like cake and having a good time, nothing wrong with that).
I do agree with some PPs that improved visitor information would be helpful, but not of the 'making-a-point indoctrination' kind. If this was thrust on us we would stick it in the bin (metaphorically speaking and possibly literally also). Our young rainbow-lanyard NT staff probably know this, as they work well with us and value what we add. They know that good volunteers in rural areas are hard to find/replace nowadays.
The only nitpicking I've got with the NT is the gender field on the volunteer surveys, which I refuse to fill in, and I avoid where I can that DEI stuff which they do because everyone does.
So PPs advocating interpretation to forcibly educate the masses - be prepared to step into the volunteer vacancies.