Several points to counter the fear and irrational selling
1. Jamie Dimon is CEO and Chairman of the largest TBTF bank in the USA, he more than anyone else benefits from the Fed's unlimited printing of fiat currency. Naturally he will criticize any threat to the current system.
2. The supply of bitcoins is mathematically limited to 21M, there simply aren't enough bitcoins for everyone that wants one. We tend to forget on this forum but bitcoin is an alternative monetary system that is immune to central bank skulduggery where we can receive our salaries in bitcoin, pay our bills with bitcoin and store our wealth all in bitcoins.
3. The middle and wealthy classes in Venezuela, Kenya, Zimbabwe, El Salvador and many other other countries need vehicles for keeping their money safe from debt collectors and acquisitive governments. That vehicle may be Bitcoin, Monero, Zcash, Dash, etc.
4. Fiat currency seems to be losing its purchasing power more every passing year, The CPI is supposedly 2% but I don't see it. The prices I pay are increasing much higher than 2% and all the other supposed inflation hedges like gold, gold mining stocks, etc simply are not working. Bitcoin seems to provides a hedge and more investors will likely reach the same conclusion.
I wouldnt underestimate Jamie Dimon. I would also think that his comments didnt just "come up", he would typically be motivated in making specific comments. Its all interesting.