I don't know where this phrase comes from, but here it goes: "All models are wrong but some are useful".

Modelling anything is hard and I think if people expect models to be accurate and to perfectly model the future without making adjustments or finding out that some assumptions are wrong, then those people just doesn't know much about statistics, epidemiology and science in general. Science doesn't just works specially when it comes to forecasting and simulating reality.

IHME model looks quite simple. It also shows very large uncertainty intervals and corrections are actually quite acceptable within that range. It doesn't surprise me that they adjust their model. This pehomenom is constantly changing. The response to the mitigation policies from the public is constantly changing. People didn't believe it to be such a great deal a few weeks ago, but now they may be more willing to follow th einstructions. Of course that will have a large impact on the evolution of the epidemic.

Anyway, I think it is right to be skeptical but once you understand some basic things about how to interpretate these forecasts