Imo the only thing that makes the Genophage harsh is the fact that it causes Krogan young to die in the womb rather than preventing them from developing in the first place. That's pretty nasty. But presumably it was the best the Salarians could manage for whatever reason.
The actual cutting down of Krogan numbers is hardly a crime though. I know tampering with another species in that way is unethical, but the Krogan really left the other races with no choice. The Salarians also reproduce in high numbers, but they use a system to manage their birth rates. Fair enough, the Krogan come from Tuchanka, where it's so dangerous that the only way to survive as a species is to produce large numbers in the hopes that enough of them will survive, but the fact that they refused to give any thought to how they should handle themselves when they expanded beyond Tuchanka is just idiotic of them. If they insist on expanding unchecked and using violence as the means, the Genophage was the only answer. The alternative is constantly culling them through never ending war, which is worse for everyone and never would have worked given how quickly Krogan expand.
I know it's not fair to punish the Krogan of the present for the crimes of their ancestors, but it doesn't really help that many of them are insistent on committing the very same crimes (Wreav, Uvenk, etc. who are just representative of a large chunk of the species). Even Wrex, for all his reformist ideas, hasn't even thought about keeping Krogan numbers in check, in ME3 he's already demanding planets and the Krogan seem keen on making as many babies as they possibly can. The way it looks, the Krogan are a ticking bomb no matter who's in charge.
So yeah, the Krogan are stupid as a collective species tbh.