Yeah, but when you're a kid, when a fantasy series you loved turns out to be a mass of obvious christian allegories and ideas from Plato taken very literally, while the last book completely and abruptly condemns one character you liked for pretty much no reason shown in the text, it's a bit of a letdown
Literally all the important main characters die in a train crash at the end and go to Narnia/heaven, except for Susan, a character who was only in one or two of the first books, barely mentioned by the end, and never did any harm to anyone or anything wrong
I haven't read much C.S. Lewis in a while, but I don't really blame him for using Christianity as a loose inspiration for a fascinating fantasy world.
Aslan does share narrative similarities with Christ/God, but he's also a lion in a world of fey.
And yeah, it's easy and disingenuous to blame writers of previous eras for not being modern-progressive. Progressiveness is... a process
Except... there were writers hundreds of years ago who weren't arseholes. People get let off the hook for non-progressive ideas if the books were written in the past, true, but that is not the same as having very... unenchanting opinions on whether or not women should grow up, for example.
Well, it rather depends on one's interpretation of 'condemns'. I can understand why Susan's treatment can be upsetting, but I think it is less about her being condemned for exploring her sexuality (if that is indeed what using lipstick is supposed to meant), and if not dying and joining Aslan in the inner Narnia is supposed to be damnation. Perhaps, but it does not seem so. As far as I can tell, she has no need for Narnia anymore, and disconnects from it by telling herself that is was a game of make-belief. She locks that door herself, and while I suppose all that lipstick and stocking business is part of it, I did not get the open, immediate interpretation that it means damnation by sex. It is, of course, rather icky and unfortunate by modern standards. I do not like that passage very much. But it is a bit odd, and I think that in the current environment, that unfortunate implication is laden with a lot more extra luggage than is due.
I, quite simply, does not see how it is quite that clear cut and how it turns the author into an arsehole. Further, arsehole is a pretty damned strong term, and seem to imply that old Mr. C.S. Lewis co-wrote
Der Ewige Jude or something, rather than a series of allegorical novels with a vaguely Christian theme that carries some very unfortunate and overly conservative implications towards the end.