How it is possible for all of them to go down? I can not find logical
answer. If they are have different chains, different communities, what
is happening for second that that can affect all the markets and all the
coins, what is that strong?
If you do not have a clue, please restrain yourself from commenting.
I would like to see and read answers from people who might know
something more, thanks in advance.
It's down to trading bots.
If bots are programmed to sell when the dollar price has dropped by a certain amount, a drop in BTC will drop the dollar price of all the alts, which triggers immediate selling of them.