This seems like a classic problem of trust, more than a discussion about gender. I can't imagine investing in a company I didn't trust enough to be candid with, but I guess that's happening, the money in it is probably good.
It's worth saying that people who have no capability to betray you in a certain way are easier to do business with. It limits downside. I'd prefer to have a reputation for defending my friends, but not being credible for a certain attack is an interesting advantage. Perhaps vulgar and obnoxious people will be easier to work with too. I will look for a way to get mobbed that doesn't violate my moral code, might as well break the seal on that so I never make anyone nervous.
It's fundamentally a problem of incentives. If the perceived downside to giving feedback to a particular person outweighs the upside, then some selfless (or stupid) people might still decide to give that feedback, but most won't.
It's worth saying that people who have no capability to betray you in a certain way are easier to do business with. It limits downside. I'd prefer to have a reputation for defending my friends, but not being credible for a certain attack is an interesting advantage. Perhaps vulgar and obnoxious people will be easier to work with too. I will look for a way to get mobbed that doesn't violate my moral code, might as well break the seal on that so I never make anyone nervous.