"Is taxation theft?" - This looks more like robbery than theft, because if taxes are not paid, then "forceful action" will follow.
I also feel really stupid when I see politicians talking about taxing gains from cryptocurrencies, with phrases like "unhosted wallets", or by attacking privacy services. They talk as if privacy invasion is a requirement, or "obligation" as per the social contract theory. I think this really crosses the line.
Statements by politicians cross the line of reason when they try to squeeze money out of bitcoiners under any pretext.