YouTube still changes the capitalization of usernames, BUT, they will no longer accept such requests since it's been made public.
I saw in the other private partner forum where Stefan from YouTube did this for a couple of regular partners, but now everyone will be requesting this so it's been closed, meaning that no new requests will be accepted, except for cases where the request hasn't been made public, to avoid an influx of requests, just like the CMS, YouTube Merch Store, and the reclaiming of abandoned usernames a few months ago which have been closed from requests due to a massive amount of users sending the requests publicly.
Sorry.