There's no question that women and men face different barriers in startups and tech. The null hypothesis is thus
(a) differences in reactions to a competitive environment are partially due to differences in how women and men are treated.
There's also no question that women and men differ biologically. The null hypothesis is thus
(b) differences in reactions to a competitive environment are partially biological in origin.
We thus have joint null hypotheses. Most commentators focus on a for obvious political reasons. Most contrarians focus on b, partially because a receives most of the attention, thus perhaps discounting a unfairly. But both a and b deserve consideration, and the burden of proof is on those asserting either ¬a or ¬b.
By stating that women are "victimized by the perception that their gender prevents them from being competitive", you've implicitly asserted that women are not in fact less competitive because of their gender, but rather are merely perceived to be so. You have thus placed the burden of proof on those who claim otherwise. In other words, by asserting a while discounting b, you have implicitly asserted ¬b as the null hypothesis.
You're in good company, of course: virtually the entire mainstream treats ¬b as the null hypothesis. Indeed, publicly supporting anything other than ¬b in the workplace is not only socially unacceptable, it is probably illegal. Unfortunately, it is also fallacious. The burden of proof is on those who assert that women's biology doesn't make them less competitive in startups and tech.
So, what evidence is there that women and men are equally well-suited to highly competitive environments? Bear in mind that nearly every highly competitive field (not just startups and tech) is now, and has historically been, dominated by men—including in far-flung locations without significant cultural contact. Contra the mainstream, ¬b is an extraordinary claim and requires extraordinary evidence.