I think the main reason is the US beat Syria. This is the main reason that has pushed up so many altcoin prices. People are pouring money into the Crypto market to hold their assets in BTC. So altcoin prices have rebounded in two days.
It seems people will always speculate and find a reason for a particular action in the market. It is a speculative market anyway, so we should always expect some few little things to affect the market value once in a while. Nevertheless, we cannot say exactly what must have triggered that value, as it may not even be any of that, but whichever way, the price shot up but the question now is can we continue with this trend or we are going to still go back lower ? Let's see how it plays out in time.
Decentralization make Bitcoin so speculative , no one could affect the market , no regulation can affected it. It's about us who play in there , no one there but each of us make a buy and sell speculation continuously.
Those factors , those reasons acts as fundamental , you can rely on it but of course not a single view from the fundamental only , there's a technical factor also who can make you confident enough to consider it as the biggest thing influenced the price movement.