Well, part of my job description involved helping to organize tech volunteers, so I guess at the end of the day that falls on me. Really it's a general problem with a widely distributed yet generally meagerly staffed campaign. There's a lot of autonomy with regional/field staffers and in turn they don't necessarily know about everything going on at the national core (where our digital/tech efforts happened). The way to help was primarily either through finding a project to help with at https://github.com/Bernie-2016 or getting involved with Coders for Sanders (https://coders.forsanders.com); I originally was a volunteer with CFS and then joined the campaign full-time after completing a few larger volunteer projects for them. But of course there's no way for a random person wanting to get involved to really know that. I'm rambling now; I don't have a good answer per se, other than that I'm sorry you had a bad experience and I wish we'd found a way to solve this problem.

Somewhat related, I've started helping out a bit with an OSS project called Code Corps that may help with this sort of thing in the future. The basic idea is that you input your interests (education, environment, economy, etc.) and your tech skills and then get matched with political/nonprofit orgs that need your skills. https://www.codecorps.org/, https://github.com/code-corps