2. Advice (which is essentially a gift of knowledge/experience) is not something you are entitled to by virtue of your sex.
3. A man cannot be said to be 'sexist' when he chooses not to give advice that could potentially incriminate him, especially falsely. If a person (whether a man or a woman) chooses to keep silent, and especially where no fraudulent aspect is involved, that is part and parcel of doing business. You are not entitled to call a person 'sexist' just because they do not want to give advice to you.
4. There are virtually no consequences to the woman who accuses. Yet in comparison, the long-lasting consequences of an investor being falsely accused in public far outweigh any advantages to the contrary. This is enough to make any man clam up, and is a legitimate cause to withhold advice.
5. More importantly, in a commercial setting, no one is obliged to give you an advantage just because you're a woman. If you expect such an advantage/benefit because of your gender, then you are being sexist. A woman who wants to do business should not posit that a man is actively being 'sexist' if he chooses not to help her. That makes no sense.
So, women are being segregated before having any occasion to accuse men of sexism, and yet you claim that they would face 'no consequences' if they actually did?
Men are refusing to giving advice, because there is past history of women falsely accusing them of being sexist when they do give it. Your claim purporting that it never happens - i.e. 'before having any occasion' - skews the time-perspective. And is against the odds that male investors have faced, which is why they now clam up.
This is nothing to do with 'segregation' - that's a silly interpretation on your part. Investors are wising up to hold their tongue, than to let aspersions be (falsely) cast upon them otherwise.