Seasonal flu already puts quite a strain on most hospital systems every year. If the rate of severe flu infection were doubled, I think a lot of health care systems would be pushed to the limit. And Covid-19 is worse than the flu, if not in terms of severity (although that is up for debate), it is in terms of contagiousness, as there is no one in the population with resistance from prior exposure, no vaccines, etc.

So it is plausible that Italy (and other countries) problems are a result of a double whammy of flu and Covid19 as it is due to the severity of Covid19 itself.