While this is technically true, the algorithm is statistically random enough to qualify for these instances; even if it were possible to monitor ever chest opened by every player on every server, it would be quite difficult for anyone (even a computer) to reverse-engineer the algorithm and even then it would be horribly impractical to use that information to predict future drops. Thus, it's feasibly random ENOUGH for its given use."Random" numbers can never be truly "random" when generated by a computer. They always follow a programmed algorithm.
Also, it's good to keep in mind that every chance is an independent event; you are just as likely to get an egg from a chest if you've open 10,000 chest and gotten none as you are when you've opened 0, or even when you've opened 5 chests and gotten 5 eggs.