If big investors are buying, this will make bitcoin more volatile, of course it could go pump and dump anytime but the fact that they are buying, they should be seeing something big coming in the future. Holding that amount, we can already consider them as one of the whales.
For small investors like us, we can always hold, if the market will pump or will start its bull run, it could come anytime, just like in the past, we haven't expect it so we didn't see it coming but the market is proven to be bullish even in just a very short period of time, which we could see it happen again.
This is just like a play safe strategy, you don't want to deal with the risks, you will just be careful about your moves in investing bitcoin that's why you prefer to hold. There's nothing wrong with that, but you also need to learn that sometimes you need to buy and sell bitcoin depending on the timing where it is necessary for you to do that.
You can't defy the risk, but if you practice risk management in your trading strategy, it will become more profitable to you as you minimize the risks. Our predictions and speculations will serve as our basis in the actions that we will do with our assets. Whales are also dependent on the market just like most of us, the only thing that they do is to hold more bitcoin without really doing what is necessary for their investment. They are the first one to suffer when to bitcoin's price drop for a long period of time.