> The article rebuked that claim

It did not. The article itself acknowledged that there is certainly reason to consider it a possibility, predicated on the fact that the people that make the thing stated as such and that experts in the field agree it's also a risk in general, but wasn't particularly high that day.

Average activity is not no activity. Average risk is not No risk.

And even if it wasn't the issue in that instance, it's not hard to reason why it's worth hardening against such a possibility in the absence of any other explanation given just days later "sensors mounted on UK weather balloons at 40,000ft (12km) measured one of the largest radiation events to hit Earth in roughly two decades."