Is this a fallacy?

In edition to the other answers here, I also want to point out that this is also the construction of a double bind. 

If the infection numbers are large, they would say that the social distancing didn't work and was unnecessary. 

If the infection numbers are small they would say the social distancing didn't do anything and was unnecessary. 

This double bind is caused by a self bias towards a certain socioeconomic political ideology that believes taxes and handouts are bad. They backwards rationalize the situation to fit their ideology and to do that they create the double bind. 

Climate deniers use this same set up for the Ozone hole. They say things like, "What ever happened to the Ozone hole that was suppose to kill us all, that prediction never happened so alarmists are wrong about the climate crisis failed predictions too" .

So, if we take action and save the climate they will say, "it was a failed prediction and the action we took was pointless just like we said" , but if we do the bare minimum and the climate crisis happens they will say, "See, the actions taken didn't do anything just like we said, its natural and socialist carbon tax wouldn't have changed nature and to think so is arrogant." 

This could be the Historical Fallacy (not mentioned by this site) as Fox are reading into a process (locking down) an effect that only took place because of that process (reduced numbers of deaths) and claiming they're independent. The only reason deaths are falling is because of intervention, so this isn't proof it's overblown.

It's also a plain old factual error. 

I have seen this "argument" presented several different ways.

What is actually being said here?

X is predicted based on current policies.
Y was the outcome based on current policies.
Y was far less severe than X.
X was overblown.

OR

X is predicted based on current policies.
Y was the outcome based on different policies put in place to (demonstrably) lessen X.
Y was far less severe than X.
X was overblown.

You can see how these two arguments are very different. The first is a reasonable conclusion while the second is not.

This particular version of this argument seems to be:

X was predicted. (no mention of policies or measures used in prediction)
Y was the outcome.
Y was far less severe than X.
X was overblown AND all the lockdowns and social distancing were unnecessary.

Generically, this is a Non Sequitur . Based on the information presented in the premises, we cannot conclude that a) X was "overblown," or b) "all the lockdowns and social distancing were unnecessary."

But be careful. We also cannot conclude that all the lockdowns and social distancing were necessary. We can reasonably claim that all the lockdowns and social distancing had a significant effect on keeping the death rate lower than it would have been without such measures (evidence from around the world supports this).  Remember necessary and sufficient. The measures we are taking are sufficient for significantly reducing deaths (i.e, they do the trick, but there may be other ways to get there as well, so unless we demonstrate those are the only ways, we cannot say they are necessary).