My 'I wouldn't be seen dead wearing...' was really what I'd not feel comfortable wearing, or enjoy wearing, rather than dictating what others should or shouldn't wear - which is none of my business (or anyone else's except the wearer!)
I've just returned from the Green Gathering festival and there was a vast range of dress/costume/garb, including a few wearing their birthday suits. I loved seeing what everyone was wearing and how they express themselves in dress, even if what was being worn wasn't 'me'.
The best thing for me was not feeling judged about what I dressed in. I felt completely comfortable and good in whatever I put on, and I can't say that's necessarily the case here in Darkest Surrey!