Running for Congress is consistent with his stated goal at the end of the article: "No longer can massive tech companies like Google be permitted to operate relatively free from government oversight. As soon as Google executives were asked by Congress about Project Dragonfly and Google’s commitment to free expression and human rights, they assured Congress that the project was exploratory and it was subsequently shut down."
If he ended the article with, "Vote for me! Maine 2020!" It would sound highly self-serving. I believe he simply doesn't see his campaign as relevant to what he's writing here.
This is his retrospective on his time at Google.
He may post other things that combine the two, but this one is clearly focused on the things he experienced while working for one of the largest corporations in the world.