I could also imagine that they didn't actually show the fee details, and just pitched it at a high-level.
As a patron, I'd be fine if Patreon just added transparency on fees, showing exactly how much reached the creator and how much went to fees, which is equivalent to "passing on" those fees. (They're effectively paid by the patrons either way, the only question is whether it's made clear what fraction of a pledge goes to the creator, what fraction to Patreon, and what fraction to processing fees.)
In my opinion, they made two critical mistakes here, and transparency on fees wasn't one of them. First, they un-aggregated charges, so that a $1 pledge costs $1.37, and ten $1 pledges costs $13.70. Second, they effectively increased all the pledges by individual patrons, rather than just being transparent about fees on the existing pledges. Effectively, they said "we're going to increase everyone's pledges by the amount of the fees (and hey, would you look at that, we get more money now)", rather than "we're going to show you exactly how much of your existing pledge goes where, without changing your existing pledge". Of course that led to a revolt.