If the author was really "point[ing] out problems with resource allocation, poor distribution of teaching load, lack of diversity among both our faculty and students, terrible graduate admissions systems, looking the other way regrading student plagiarism, and our neglect of our undergraduate programs" from the start, then I'm not surprised at the outcome. While I'm sure most or all of what the author complained about were true problems, the fact is that your colleagues (1) already know; (2) know a lot more than you do about _why_ things are broken (or the reasoning behind what only _appears_ to be broken); (3) might already be working to fix it; (4) might be _responsible_ for what you're ranting about, which may well be a huge improvement over previous iterations of the policy/system; and (5) don't appreciate being lectured about how broken everything is by someone that doesn't realize #1-4.

Tenure is a big commitment by the department and the university to your career. No matter how successful you are on the objective criteria behind the selection, you also need to be someone the faculty can envision being glad to work with for the next few decades, and who they think can be effective in improving the department in the future. If we believe the author's own evidence, then I would have been inclined to vote nay as well.