I don't really know what you mean with "controlled", but there is definitely no mechanism that makes all the other cryptocurrencies automatically go up or down in price when Bitcoin is also going up or down. In reality though this still is the case most of the times or at least on a grand scale and there are a few reasons for this. First of all a bear or a bull market is always happening withing the whole crypto market and not only for a few projects. Bitcoin is also still by far the leading project in the crypto space. So it is not really surprising, that most of the time Bitcoin is the first project to make a price move and then the other projects are following.