Meanwhile, Altcoins are making large gains vs. Btc.
I didn't see that. Alts also went down when bitcoin goes down. Everything is in bad shape and the gains were much better with bitcoin before it has corrected.
but what I understand is sentiments and those sentiments were shaken when someone moved bitcoins from a 2009 wallet, and rumours began to spread that those were Satoshis bitcoins.
This brought fear and people started to sell as fast as they can because they thought that bitcoin will drop that much. But as we see, it's recovery a little by little and the fact that it started on $6,900-$7,000 is already a gain to see it playing to $8,600+.