This is not an issue of partisanship. It makes sense that Dropbox would want an accomplished, high-level, well-connected individual on their Board of Directors as they prepare for their IPO. There is no doubt that Condoleezza Rice is an extremely brilliant and accomplished individual, having obtained her Masters degree at only age 20 (and a number of other impressive accomplishments).
Choosing Condoleezza Rice for Dropbox’s Board is problematic on a number of deeper levels, and invites serious concerns about Drew Houston and the senior leadership at Dropbox’s commitment to freedom, openness, and ethics. When a company quite literally has access to all of your data, ethics become more than a fun thought experiment.