in this context downplaying the severity of the drop people actually experienced

Well.. no, it isn't downplaying it. It's representing it perfectly. That's quite literally the point.

When graphs aren't zero-based, you immediately make a bad intellectual assumption as well as an 'emotional' reaction to the size of the graph. That immediate bad assumption poisons the way you think. We can't eliminate that 'emotional' reaction, but we can (and do) standardise it and we consequently learn to gauge appropriately.. only so long as people keep to that standard.

The only time you shouldn't zero-base a graph is when the change is too small to reasonably decipher without enlarging the scale. I'll die on that hill. If you do it for any other reason, you are just engaging in misleading emotional manipulation. There's a place for emotional appeal, but by means of making you misunderstand reality isn't it.