Many companies don't retain most people past their probationary period. After you probationary period you are often eligible for benefits or perks the company has no desire/intention of paying for (for example mandatory obamacare). Since they don't legally need a reason to "not retain" you (as opposed to fireing) it is common for employers to use whatever B.S. explanation they can find. I'd bet there's not much you could have done to get them to choose to retain you. If you frequent this gym, I bet they have an unbelievably high rate of "turnover."
Caption this Meme 