By using "slavery" to refer to life under an oppressive regime, Grumpy Old Tallpine is squarely within the best tradition of Western political rhetoric. The Founders, many of whom knew from experience that they were NOT literally slaves, nonetheless spoke of slavery in the less literal sense. They were not wrong to do so, even if they were sometimes ironic.
GOT is complaining of a lack of self-ownership among supposed free men. "Limits on my conduct and I have to pay taxes," can mean a lot of things, and GOT was talking about excessive limits and absurd taxation. "Working to support the other 50+ percent of the population, being told what you can and can't put in your body, being told what kind of toliet you must have in your house, being told that you must buy health insurance, and being subject to search anywhere you go, etc etc etc..." Is that literal slavery? No, but not everything is meant in the most literal sense.