Everyone is afraid of „otherwise“ without anyone having witnessed it before. My guess is, we are trading short / mid-term stability for decreased long-term efficiency / productivity
Which in my opinion is acceptable, because it's the short-term chaos that is the most likely to bubble out of control and turn into a long-term chaos. Imagine the chaos that would besiege the world if there was a risk of bank runs and people not even being able to pay for food anymore. We're only three to six missed meals away from absolute anarchy and violence in the streets.
The Fed is doing a great job with current tools but they're a bandaid for bigger issues. It's not a question of if this becomes an issue it's a question of when. The longer you let the bubble build the harder it is to deal with it. Economic stagnation similar to Japan... is tough to deal with.
Beats continuing to bailout the corporations instead of the people.