Why this matters (just my theory): previously all that new money went to banks, the stock market, VC, etc., not so much directly to consumers. So we saw the stock market explode, but not so much for the price of eggs. Now we have supply chain shortages and people itching to spend, so we're seeing CPI explode.
Raising interest rates won't help now (again, my theory), because they do nothing to discourage consumers from spending, other than maybe to slow housing or other purchases requiring loans. In fact, I can't get a better return from current interest rates (actually I can still get approximately 0) than prices continue to rise, so I'm incentivized to keep spending.
The Fed needs to convince people to start saving/investing (stop spending), otherwise nothing will change (for the better...)