I have close to 30 bettas (and over 50 fish) and I wouldn't class myself a hoarder. All my bettas live in a minimum of 3.5 gallon tanks that are individually heated and kept fastidiously clean.
I am hoping to consolidate the males into a large barracks system to cut down on electricity usage and costs, and I can easily see how someone could properly care for numerous fish if they had several barracks in place.
Breeders often house upwards of a hundred adult/juvenile bettas. I don't think they would be classified as hoarding.
Hoarding only becomes a problem when more and more fish are accumulated at the expense of the others. If you are not providing appropriate care for the fish you currently own, you should certainly not be in the position of purchasing any others.