The same goal as of any other member - to attract public attention.

I did not quite understand what visitors come to this kind of sites when I built it, but now I can clearly see 2 types of people (I'm not saying there are only 2, but those I can see clearly). One type simply enjoys sexuality and shares photos, feeling, etc. But another type is obviously consists of very unhappy people who lack attention from others in real life. Sometimes they even psychologically sick, but mostly just desperate. And they do here any kind of things to attract attention to themselves.

Funny that many people who seem to despise them in fact give them exactly what they want. When you complain, curse them, try to reason them, try to reveal them in public, etc., you give them attention and an illusion that they are worth something, that they are important in some way. Does not matter that this way is negative. For them bad reaction is better than no reaction at all.

Hence the obvious way to deal with them: if you do not like them - simply ignore them. Just don't forget to report pics stolen from paysites if you notice them :)