it is a personal choice to have a photo on a profile or not. It is not mandatory at all.
This is a small site by comparison to many others, and the most outstanding feature of it is that we have none, or rarely ever get a scammer in here. The few that do sneak in are not here long ( usually only hours before they are booted).
The picture / avatar is something we tried to get people to do by offering points to post one, and also telling them that they will be a featured member and get points after they upload pics / an avatar.
But that is all we can do. This is not a monarchy where we make mandates of people to reveal their privacy. It is up to them how much they want to reveal to the public about themselves.
While it does not make one bit of sense to me to have a profile on a dating site and NOT post your picture ( as it is similar to a Resume or C.V. for a job) some people want to have it that way for whatever reason. Maybe they are so good looking they'd get so many PM's they wouldn't be able to answer them all
but I really doubt that is the answer...