A math student/coder I met at an entrepreneurship event told me Less Wrong had good ideas but was "too pretentious".

This person might have been in the same place as a math grad student I know. They read a little Less Wrong and were turned off. Then they attended a LW-style rationality seminar and responded positively, because it was more "compassionate". What they mean is this: A typical epistemology post on Less Wrong might sound something like

There are laws of probability; you can't just make up beliefs.

(That's not a quote.) Whereas the seminar sounded more like

We'll always have uncertainty, and we'll never be perfectly calibrated, but we can aspire to be better-calibrated.

Similarly, an instrumental-rationality post here might sound like

To the extent you fail to maximize some utility function, you can be Dutch-booked. Give me a penny to switch between these two gambles; give me another penny to switch back again. There: You have given me your two cents on the matter.

Whereas the seminar sounds more like

You must decide alone.
But you are not alone.

Of course, both approaches are good and necessary, and you can find both on Less Wrong.