The Olympic Games; are they really fair?

I get very irritated when I see tennis players like Djokovic, Murray, Williams sisters etc., taking part in the Olympics. I know that it is not just plucky amateurs any more, but these professional tennis players are full time, with psychologists, dieticians, physiotherapists et al, and they are playing at the same time as others who are having to put their careers on hold/work part time in order to train, attend qualifying competitions with little or no funding, Bethany Shriever had to crowd fund to get to Japan for heaven's sake! I know not all sports can get funding, but seeing Murray at the same games as Shriever is making a mockery of the Olympics I think.