You don't have to tip your waiter at the restaurant. But their salary is fundamentally dependent on you tipping them ~15-20%, so by not tipping them, you are effectively stealing from them. Similarly, not subscribing to people I watch heavily is in effect stealing from them.

To be clear, I don't actually like this model of payment. I'd much rather there be a system that could automatically distribute a pool of money in terms of how much I watched.