Most fish offered for sale in the trade go into a small home tank with many
different species. It is unusual for the typical home fish keeper to breed
except by accident. Hence the expected end result is self limiting.
For people looking for an attractive moving display the cross breeds and
injected fish are a simple solution.
I would not object to a cross being sold in shops where it is properly
labelled because the buyer has been treated honestly. Where crosses are
knowingly sold without proper notification I would object.
Serious collectors will not buy crosses except as feeder fish.
People buying to complete a colour scheme can be well served by crosses.
Monty