In my opinion (I am late as usual!) you were not cruel; I would classify you as "curious." But as a breeding tactic, it is bit useless if they are kept together and allowed to "fight" to the point of physical contact.
I have put two males together while the female is in the cage and let them stay long enough to get their "dander" up. Beyond that, it is a waste of time and if they try and dominate each other with their hempes, I remember reading that they can damage each other (sorry don't remember the source).