Is there any explanation why BTCs down movement triggered a down movement for XMR?
Yes it was interesting to see the price of Monero mirror the price of Bitcoin during the drop.
Anyone have an explanation why the price has been so closely tied to the value of Bitcoin?
It got that way from just before the time of the GUI release - we started to maintain price at (roughly) 0.015 all the way up as BTC increased masively.
It meant we increased in value in USD terms hugely - to an ATH level.
Right now I wish we were maintaining USD levels as BTC drops, but we cannot have it both ways! It does mean BTC up, both up, but conversely is seems BTC down, XMR down. We're looking pegged to BTC, so we no longer have that hedge position of inversely related moves we used to have.
It's probably XMR now being in the top 3 or 4 alts - we are now more subject to crypto market sentiment
overall.
It may change, but it is a distinct realignment for now. Maybe is is because XMR has grown up.