It is not nonsense
Of course it is nonsense!
Battery capacity and discharge current do not neccessarily have anything to do with one another. They sure become proportional when combining batteries in parallel. Otherwise high discharge current is a criteria of battery technology. When using small and light batteries they will have of course a higher "C-factor" than high capacity batteries, although this is not proportional.
A moreserious value would be the permanent allowed current flow (upto the safe discharge voltage), and the peak current. You find those values in the datasheets if you buy a high quality battery.
For low price batteries a major issue seems to be at the moment that the capacities given are not reliable. Many of them have half of the announced capacity only. So multiplying things might give you the wrong impression....