As a guy who has never worked in a large company, but has seen start-ups I've been involved with turn out both wonderfully successful and less so, I can tell you that creating a 'culture fit' template for a start-up is essential in being the former rather than the latter. For as much as people who have never run business units or companies want to claim it is only about 'the work' and that each person can somehow be in a performance bubble, that just isn't the case. At a small start-up, culture can kill you in a way that won't happen in a larger organization.

But is looking for the best personality fit discrimination? No, it is not the role of any CEO, hiring manager or shareholder to fall on the cultural sword and engage in social engineering at their own expense - people need to hire the best employees and that means thinking on a lot of levels when companies are small. But the horror stories you read - all anecdotal - about how various people are treated in tech companies make it sound like misogyny and discrimination is the norm. 

People who see everything through a prism of social justice are the people you have to really think about before hiring in a tech start-up, no matter how good their work is. Small companies, just like larger ones, aren't rife with uncaring people in 2013 but they are rife with people who will provoke those they know have a hot-button topic. If a guy shows up and wears Python t-shirts every day, the kinds of eccentric, adventurous employees who join most start-ups - they are doing it for far less money than successful companies pay - are going to make comments about Python just to get a reaction. 

Gawker compiles some isolated instances and makes them sound like sexism is rampant in a recent piece on Culture Fit - a veteran programmer is given a quiz on javascript, for example. That's only because she is a woman, it is implied. I have to tell you, I have never hired a programmer, "veteran" or not, without giving them a programming test. It has nothing to do with gender or sexism, it has to do with seeing what someone's brain is about. You learn a lot about how someone thinks by seeing how they write out code to make stuff happen. I have never hired a really bad programmer but I have interviewed a lot, with advanced degrees and a lot of experience. "Veteran" status is meaningless. Saying it is sexism when 'veteran' women have to do it isn't valid. 

Tech people are not always socially adept - stereotyping men in technology that way will bother absolutely none of them - and that means they often talk to each other in ways that are not really conducive to esprit de corps. The only thing that can make it worse is introducing someone who is going to demand the personalities of the people around them change. That is not a constructive addition to a company, because then people are talking about 'style' rather than 'substance'. 

The people who have a cultural beef with the technology sector play psychologist and declare that these tech guys who were shunned by women in high school now enjoy the chance to shun women back - aside from lacking an evidence-basis, it is so simplistic as to not merit consideration. The reality is more subtle. As Pretty Little State Machine puts it, corporate culture is not about free lunches and spending an afternoon a week working on whatever you want.
Culture is about power dynamics, unspoken priorities and beliefs, mythologies, conflicts, enforcement of social norms, creation of in/out groups and distribution of wealth and control inside companies. Culture is usually ugly. It is as much about the inevitable brokenness and dysfunction of teams as it is about their accomplishments. Culture is exceedingly difficult to talk about honestly. The critique of startup culture that came in large part from the agile movement has been replaced by sanitized, pompous, dishonest slogans.
I can make that a lot shorter, though people who have never been in start-ups don't really get what I mean - I have been able to hire and fire people in companies I have joined, but I have never once been able to change the culture. It's important that you get it right in the beginning.

Rules and memos won't do it. The only thing that works is making sure you hire the people who match the culture you want to have in order to get your product built. No one raises money to reshape Silicon Valley culture, they raise it to build products. 'Do no evil' absolutely did not appear in any documents when the Google guys were walking along Sand Hill Road looking to get funded.

So if someone says a potential hire is not a culture fit, and you read way more into it than is there, you are probably not a culture fit either. It's okay, work for a different company - there are as many cultures as there are companies. But attributing a secret agenda to tech managers and employees is conspiratorial and, like most conspiracy claims, not evidence-based. Business people care about winning and then buying a Porsche, not holding back anyone.