Because there are newcomers who make bitcoin prices go down little by little because they panic to see the price of bitcoin dropped just a little and sell it because of it. Even though it should be if they are new, it is better not to directly invest in it because there are many risks they have to face. It's better if they know in advance about the new bitcoin investing in it.
We can't avoid that because there are people that are just going to invest in bitcoin without any knowledge or preparation just like they are being driven by the hype in the internet and that is why they are investing or putting money in bitcoin. The price of bitcoin is rapidly going down but it is best to get those cheap bitcoins rather than join the panic sellers.
Further downfalls are observing in the price of Bitcoin which indicates our actions as we sell right after a little increase or improvement in price which make the price with another downfall. We should remember that we are in a long term investment and should think like that by holding Bitcoins till higher market for huge profit rather than wasting our time for less profit is foolishness.