The defining difference about paying money to a corporation in exchange for a product is you're paying for something already there, an agreed exchange of value. The whole point about a donation is it's given not in exchange for doing any particular task, but gratuitously.

It's not a weird sentiment to want to know what benefits a gift is providing. That's all people are asking for when they want transparency around donations: tell us how you're benefiting from it so we can feel good about gifting you.

Is it necessary? No. The point being made is that people would be happier and potentially gift more if there was more transparency. If your argument is transparency costs more than the extra gifts then the solution to that is - ironically - be transparent about it and people might gift means to make transparency cheaper and make donations viable.