Well, all taxation can be considered unreasonable. It's true that the system doesn't work similarly for cryptocurrencies and stock, but that's no reason not to pay your taxes. It's not like the system came as a surprise to the people who sold crypto in 2017.
My personal experience is that most Finns whine about taxes, yet they also complain if healthcare and infrastructure and education isn't perfect and completely free. I feel that as a smart responsible adult it's better to be happy that I have income to pay taxes for, and be grateful of everything the taxes pay for. If I didn't like the way things are done in Finland, I'm free to move elsewhere (or take up politics, get elected and change everything the way I like it).