Shy? It's an open site so maybe they don't want their activities on here followed by someone known to them in a professional capacity. Maybe ask them?

It's their prerogative. Why do you wish to dictate what people should or shouldn't do?

I'm all for pictures 🙂

i am personally not looking for somebody but if one was looking wouldn't one want to know what the other person looked like. Yes i get this site is about the outdoors i.e. walking, cycling etc etc but is it not also about meeting somebody, is that not what duo means.

Looks are only skin deep 🙂

Everyone has choices, preferences or reasons.
I can understand that some need or want to keep personal and professional lives distinct and separate.
It is also interesting meeting people for the first time NOT knowing what they look like and also great getting to chat to people and understanding them a little.
Since I am not looking for anyone maybe I have a different slant but if I were , I could run the risk of prejudging and missing out, or vice versa.
Peoples choices and reasoning which we may not know.