How is Google going to know what party you voted for, when votes are by secret ballot? Voter registration databases, which are public information available for a small fee from state governments, are far more likely to yield a profile of your voting behavior than your gmail contents.
You have the choice of not seeing targeted and relevant ads, or of not using gmail at all. Try Fastmail for instance. I don't see the need to bash Google for doing the right thing on security.
Not only that, but anyone can opt-out of interest based ads for Gmail. Just go to Ad Settings (https://support.google.com/ads/answer/2662922?hl=en)
You have the choice of not seeing targeted and relevant ads, or of not using gmail at all. Try Fastmail for instance. I don't see the need to bash Google for doing the right thing on security.