They don't have a clue. OR, they are lying about their reasoning. The numbers are bogus.
A number is just a number. One possibility is that if the Fed really does stop, the dollar will devaluate faster and the dollar denominated price of stocks/assets will accelerate as a function of inflation. It is one thing to have the market hit $14,000 with low inflation and quite another to do so with high inflation. If the $14,000 buys you more in gallons of gasoline then, then $11,000 would today, we are doing good - otherwise we are screwed.