Hi there
The thing is, Betta splenden are not like Gourami when it comes to either breeding or their character, so this comparison is a poor one. In Thailand and other Asian countries, Betta have been bred the same way for over 150 years, so its not a case of betta breeders doing it in reverse at all, more todays breeders following on the traditional techniques of those early pioneers.
There are many reasons why a male betta may be aggressive towards the female, but if the pair are treated and conditioned correctly leading upto the spawn, any damage will be minimal.
The reason for having the female in a chimney/jar and the male lose, is that the male can stake his territory and choose where to build the nest. It is also because in their natural habitat it is the male that will approach the female, not the other way around.