I've heard two "meta hypotheses" about what's being discussed here:

i. Equities markets rise and fall depending on the economic numbers and other metrics regardless if they're true or artificial (in essence, to the algorithms who produce ~90% of the trade daily volume, it doesn't matter one bit if the Fed is artificially keeping rates low or if Congress is mortgaging the next 30 years of prosperity to give out stimuli).

ii. JPM, Blackrock, Citi, BoA, etc. with the tacit (and sometimes explicit) backing of the Fed and US Treasury are engaged in a coordinated "sentiment lift" via equities. So there is not a little bit of concern of "equities getting ahead of themselves", because they're willfully collectively ignoring where the economy is or where it's going and are not afraid of a "reconciliation reckoning" because they (Fed, Banks, UST) sort of call the shots.