Some people just look for reasons to be angry. Also, some people lose the perspective that this is literally the very first beta in a series of betas that will last for at least 3 months before iOS 18 goes live, by which time many, many more third party app icons will be better adapted for tinting and dark mode. 🤷♂️
That said, I played with the tinting, looks cool, it's a smooth experience setting it up and, overall, I think they did a good job with it. Personally, I prefer the native colors of the icons since my eyes are trained to identify the app I'm looking for by sight and having them tinted really interferes with that even when I already know where they are.
So, not a feature I see myself using, but for those that want it, feels like a pretty nice implementation.