But the Halo Effect page that you linked says that males were influenced by the halo effect when rating both male and female subjects so this isn't a strong argument for not hiring/investing in women.
And in a MythBusters I watched the other night, they "Busted" the myth that men get dumber around an attractive female. I'm pretty sure it was from the newest season if you wanted to look it up.
Not saying, of course, that this justifies any kind of harassment, just that maybe some of these investors have learned in the hard way that their judgment gets clouded when dealing with women.
[1] http://en.wikipedia.org/wiki/Halo_effect