Just wait. The message will turn out to be a trolling exercise on the part of Elon Musk. He's the only person with the means, opportunity, and evidently the motive to simulate a shitpost from Alpha Centauri.
Only if the aliens have a feudal system where the wealthiest are the lords/ladies.
If it turns out they are space democracies not so much.
What if they are both? What if they didn't reach a global government and live in a dynamic political landscape composed of several government systems and variable peace/conflict periods?
I told you, We're an anarcho-syndicalist commune, we take
it in turns to act as a sort of executive officer for the week. But all the decision of that officer must be approved at a bi-weekly meeting by a simple majority in the case of purely internal affairs.