IMO whether the good is "mandatory" or discretionary is completely irrelevant. That just makes you feel less bad about the transaction.
To their credit its a question of how the company handled the tariff fee. If the company 100% absorbed the cost themselves and did not pass it to the customer then there's no issue. If they did pas the cost to consumers then it's fair the consumer is refunded for the cost.
The problem here is that Sony didn't explicitly say that. Note they never explicitly state they did not bake in tariff costs to their prices, They're just claiming that they raised their price to meet market demand and sidestepped the question. They very well could have jacked the price for tariffs, saw no decline in sales, and just left it there because, well, capitolism.