He may have downplayed the severity, but it's light years away from claiming it's a "hoax". One can reasonably debate whether he did the former, but the latter is flat out lie. It's not ok to lie, even about Trump. There's a huge difference between choosing how to react to coronavirus (a lot of people were unsure initially how severe it is) and flatly denying it is happening. It's OK to argue that Trump was wrong on his chosen reaction, but it's not ok to lie that he called it a "hoax".
> It follows that the "hoax" is referring to the opposition party making a mountain out of molehill.
The "hoax" was about the claim that he did poor job handling the coronavirus. He thinks he did great job and his opponents are wrong. Not about that coronavirus epidemics doesn't exist.
> Which is fine and good!
What is not fine and not good is that people are ok with lying as long as it hurts the other tribe and helps theirs. Not ok at all. It's not a matter of "interpretation", it's a matter of twisting facts to the point where it becomes outright falsity.