You see this in Bitcoin because it was a huge rise last year and people got struck by FOMO.
But it's not about millennials, I think that it's spread between all the generations.

And yeah, the ones getting in debt for buying Bitcoin are in a trouble now and the propaganda machine targets them fiercely. Some sold at a loss, some will sell at a loss, some will hold.
Bitcoin should rise again when a new market cycle starts (of course, there's no guarantee, it never was). Some did gain nice money, some may gain nice money in the future.

There needs to be a good combination of luck and patience in all investments. The ones getting the right combination win, the others lose. Sadly can't everybody win.
The rest.. is just bombastic news and propaganda.