You're looking at this as a single product when, actually, it's part of a package. If you pay $20 to park your car and that $20 more than covers the cost of electricity why should they pay more? Why get all hung up on someone getting more than you? For that matter, when I go to through the drive through at McDonald's my meal should be cheaper because I'm not using the tables and chairs that they put in the lobby -- why should I have to pay for someone else's ability to sit when I never use it?
So funny (ish) story about a former friend of mine (you'll fine out why in a second). He used to complain about "handouts" like this all the time. In college he got pissy with me one semester because the professor used to "sell" her students her books, which were basically a set of short form test essay questions. And her tests were open book. The deal in her class was that you buy the book for $1 at the start of the semester, and if you pass, you get $5 back when you turn the book back in. (It was actually a hard class and the book was more of an outline, if you wrote exactly what's in the book you would fail the class). He also once (and this is why former) complained about handicapped parking being in the front saying that just because someone is handicapped doesn't mean they should get closer parking.
So the funnyish part of this story. I thought for a while just this was a "bootstraps, everyone gets the same treatment" type person. Nope. Turns out this person was gaming the system however they could. He worked in a retirement home dinner area, and when he would be allowed to get his employee meal would often double up on what he was taking so he could have a "free" meal later. When Hersheypark was closing, he would go to all the venders on the way out asking if they were just throwing stuff away and could he have it.
Turned out (after I stopped being friends with him) that he would complain all the time when there were benefits to something that he couldn't take advantage of. Basically things like free EV parking would piss him off because he couldn't get it, but if he had an EV he would do something like buy a BGW pass and abuse the ability to park there so he could keep his car charged "for free".
Sadly, based on past comments from people and their stance here, I'm seeing some of the same thing. People who would game the system of the dining pass and going to the park for dinner and leaving. People who knew each spot to go to when to get things for free. People who complained when there 10 year old grandfathered rate was forced to match the 'fair share' of what everyone else is paying. It sounds like some complaining about this benefit being a potential good thing are more so upset that its a benefit they can't abuse than understanding how it's a good thing.