Well you don't want all-male cyps so I guess I can see their point. What I do is buy 2X as many unsexed juveniles as I want and then rehome extra males.
Just thought you might want to know I decided to stick with Tanganyikan and am adding colorful cyprichromis.
I got impatient last time and took the chance that some would color up that never did. It might take me a long time, but I'll just buy those males that are already showing they will have good color.