Did I say mandatory? I meant optional! You’re “free” to die in a cardboard box under a freeway as a market capitalist scarecrow warning to the other ants so they keep showing up to make us more!
Yeah it’s really very simple. That person is being purposely obtuse for whatever reason (either they have a ton of unrealized gains that they themselves have been using as leverage for years, or they believe that they are a “temporarily embarrassed millionaire” who will need these lax tax laws in the near future when they are suddenly extremely wealthy somehow).
As soon as you use those “unrealized gains” to make more money, they become realized and should be taxed. Simple.