The good thing about principles is that they’re timeless, and they don’t care if you believe in them or not. Yes, it would be nice to have better people in politics, but as James Madison observed, “if men were angels, no government would be necessary.”
Hypocrisy isn’t a virtue, but it isn’t the worst thing in the world either, because at least it recognizes the value of the norm it pretends to respect.
But as long as we’re pretending, why not pretend to be principled? Take a few honorable stands against your short-term political interest, then ask why the opposition won’t do the same. Maybe start by denouncing anti-Semitism in your own backyard while demanding your neighbor do likewise.
Your motive might be cynical and self-interested, but if it’s good politics and leads to a decent outcome, who cares?