I think he means "the whole market is in a downtrend". Which is totally true. Out of 200+ coins on coinmarket cap, only 10 are green in the last 24h.. so I think it's a fair statement.

When did all the alt go boom? When btc price went boom. When do all the alts go down? When btc goes does.

Alts follow btc. A very fair statement about alts would be that they are basically leverage against btc. The rewards is exponential but the risk also. In crypto where you have very limited ways to leverage, alts are great for that.

And what better than to choose the likely new home of GPU miners.