It's possible that either decision attracted a different class of buyer. Altcoins have been dumping recently as people sold their holdings to buy Bitcoin in case there was a fork in order to get more of the forked coin (like what happened with Bitcoin Cash). Canceling Segwit2x may have caused traditional investors (e.g. those with less risk appetite) to feel that there are fewer questions about which chain survives a fork; they could have been waiting to put money into the market until there was a clear sense of which Bitcoin fork would be the successful one.

Altcoins are surging at the moment, so I believe that lends some credence to the first group being people trying to move into BTC to get more free coin.