I have 5 people in my family. If we each own two rifles, two shotguns, two handguns, that's 30 guns. We don't own that many weapons, but, we could. We might. We might also own bow hunting equipment. (I don't think that fishing is relevant, but many families have a lot of fishing gear too.)
It starts to get rough when people start to say, you shouldn't have that. You shouldn't have that much money. You shouldn't have that big of a house, you shouldn't have that many cars, you shouldn't use that much electricity or fossil fuels, you shouldn't have that many children, you shouldn't drink that big of a soda, etc. etc. etc. It starts to sound like the nanny state.
Red flag laws are a bit scary because they could be abused, but they might help. That said, people can do very mean things to one another. In my extended family, a husband had his wife committed to a mental institution against her will (years ago). I have also seen divorce cases where people are out to damage each other as much as possible. People can be very mean to each other. I am not sure how to balance the protection vs. the freedoms, and so it is important to have judges who are not gun-grabbers or out to get people.
https://en.wikipedia.org/wiki/Red_flag_law#targetText=In%20the%20United%20States%2C%20a,danger%20to%20others%20or%20themselves.
States that want this can pass these kinds of laws.
From the article you shared:
<i>Under federal law, gun stores are required to report multiple handgun purchases to the Bureau of Alcohol, Tobacco, Firearms and Explosives but not multiple rifle purchases.</i>
I don't think that it's unreasonable to make a note if it seems that an individual is making a lot of firearms purchases, to where it seems unusual. Of course, determined people will get firearms and diversify their buying and sources. I wonder how well the handgun requirement has been working so far.