The sentiment is repeated like a religious mantra and I believe it is rooted in a collectivist reaction in the minds of many. The idea is that if we all comfort each other by repeating the lie that we're all in the same boat, and if everyone believes it, then the threat of the outbreak along with the economic collapse will somehow simply "disappear".

The notion that "we are going to get through this together" seems to be based in the assumption that the crisis is going to move quickly, and if we hold tight, our sacrifice will be minimal and all will go back to the way things were before. This is simply not so.

I highly respect the ideal of giving hope to others whenever possible (as Aragorn says in Return Of The King "I give hope to men.  I keep none for myself"). However, hope has to come from a legitimate place. It has to be based in some reality.