> He kept asking me strange questions that presupposed I knew how to negotiate with large entities like government agencies... as a developer.
Perhaps that's part of the skills that are needed to succeed at 18F. It sounds like these folks are in a sort of consulting position where they help other government agencies with technical projects and policy efforts. Take a look at the 18F Innovation Specialist GS-14 and -15 roles: https://pages.18f.gov/joining-18f/pay-grades/ - based on your background, they might have expected you to fall somewhere around, I'm guessing, GS-14 (1). Some of the qualifications required are:
> Knowledge of and expertise in driving and implementing technology solutions that overcome significant challenges resulting from complex or bureaucratic environments, or technically difficult problems
> Skill in oral communication to present sensitive recommendations to higher authority, to obtain compliance with policies from activities nationwide, to articulate positions/policy of vast technical complexity, and to represent the agency on task forces
> Comprehensive knowledge of and expertise in all stages of product or business development, and ability to lead complex technology and policy initiatives from inception to implementation
Bureaucratic environment is right there in the job description :-) More seriously, this sounds like a reasonably senior technical role in which one would likely interface with other agencies in the way you're describing. GS-15 is even more demanding. While it's disappointing that the interview expressed condescension at your lack of expertise in this area (and expressed anything other than professionalism), I can understand given these qualifications why they'd probe into those skills. It appears they're looking for technical leaders, and not exclusively heads-down individual contributors -- this makes sense to me given their mission. These positions seem to be about influencing the government through policy and technology initiatives, and influencing other government agencies (which is harder than influencing one's local environment), not just delivering technical projects.
I am not trying to excuse the interview experience that you had, just to be clear. I'm just making an observation about the kind of challenges they appear to have, and the kind of qualifications they might be looking for in candidates to tackle them. Innovation Specialist GS-14 and GS-15 sounds like pretty interesting roles. I am personally glad that they expect such leadership from technical specialists; this kind of broader influence is key to career growth as a technical person past a certain point. Organizations that don't expect this and foster this in individual contributors are organizations where you need to move into management in order to keep moving up.
However, it sounds like they could have done a lot better job communicating with you respectfully and professionally, as well as conveying what they're looking for.
(1) I know nothing about 18F beyond what I've read on these sites, nor about government pay grades. I'm just taking a guess based on your industry experience, and by comparing the 18F job role levels to the qualifications expected of candidates with similar background in private industry.