There is no such league to be very honest. The faces being covered is a need for operators involved in Counter Terrorism work where they may have to undertake recce etc and their faces should not be disclosed publicly for this specific reason.
The hiding the faces otherwise is an attempt at magnifying the mystique around the SF and not much more.
In the old days, we used to be very mindful of troops from 19 Baloch being photographed etc. and this was not allowed. As you can tell now, SSG pictures are abundant. However what you do not see publicly are pictures of the anti-terrorism team of the SSG due to the specific nature of their work.