Canceling public events

"Canceling public events because of the threat of x doesn't make sense,

This implies that the threat of x is not decreased by limiting contact frequency/density, which is a fact-based issue, dependent on how x is transmitted and what the public event involves.

there are a lot of other possible sources for infection"

This is true, but irrelevant, similar to a child's argument opposing washing his hands because they'll just get dirty again.

Imo, the first proposition is simply wrong wrt coronavirus/Covid 19 (for most public events), so no conclusion that relied on it is valid.

If the facts of transmission (assertion/proposition #1) were true, the second assertion would still be irrelevant (non-sequitur), and on logic alone (a/p1=true) would have been sufficient for the argued conclusion.  A fallacy of petitio principii has no basis for rejection because it was noted, when it happens to be correct.

Canceling public events because of Corona doesn't make sense, because there are a lot of other possible sources for infection

This ignores the spectrum of "infection," particularly the rate of contagion and the harm the infection can cause. This might be black and white thinking (cognitive bias) or just plain ignorance.

Perhaps a reductio can help here. Would we say that cancelling school because of a major snowstorm doesn't make sense because there are a lot of other possible sources of danger when traveling to school (e.g., car accidents, abduction, meteor, etc.)? No, because the reason we give could be the most pressing source of danger.

It simply doesn't follow (Non Sequitur) that "it doesn't make sense" that we shouldn't cancel public events because of the coronavirus given that there are other possible sources for infection. This might even fall under Appeal to Possibility .

Maybe Logic Chopping? There's an example on the page that seems to match this one.