Part of hacker culture is judging someone by ideas, which is why we're known for the t-shirt and shorts attire. But I don't think it's fair nor helpful to judge someone by their attire at a post-work event.
We know gobs and gobs of NYC's tech talent works in the financial services industry. I'm happy to see the diversity, even if I got a few pitches from folks looking for a l33t technical co-founder.
You should reconsider if it's more lame to wear a suit or to be judgemental.
Please don't make assumptions.