the people who just want to see the people having sex are not "voyeur" they have nothing to with voyeur sites.
A voyeur first imagine and dreams at what he expect to see, he searchs looking around some part of his dream become real and part of dream by part of dream built what his imagination created. Each step of discovery increases the pleasure and excitement . The icing on the cake is to discover the dream in real life. The excitement could be so great that you can loose your mind.For example: you dream of a pretty girl : first of all you imagine how she must be color and lenght pf the hair,colour of eyes, height,form of breast, of ass; lenght of legs ,weight etc each part of her body. When you have your girl in your mind you can start the discovery. You will not find all parts of your dreamed girl in only one personne Your imagination will collect all your discoveries and built step by step your dreamed girl.
Voyeurism is a continuous research of a dream never reached. If you will just see people having sex go to porn sites.
That is what I think about voyeurism