The answer lies in who the governments are that are saying that. They're the advanced economies which are well developed and have good regulatory systems, the ones that have little to no risk of hyperinflation. And, for them, deflation is worse than some (non-hyper) inflation. It's also much harder to get out of, Japan is still sort of stuck 20-30yrs later despite taking more and more extreme measures.
To circle back to the parent comment topic, ie. people think printing money always causes inflation: You mention Japan. They have printed so much that their central bank owns about 45% of the national debt. And they still have no inflation.
>we keep having mysterious debt-fueled collapses.
I don't think they're that mysterious. Most seem to be caused by human irrationality / group-think (bubbles), in combination with complex financial instruments that magnify the effects of a burst (ie. unwinding of massive leverage).