It’s true, as @Eau Rouge indicated, if you add an item to be excluded from Spotlight search, Spotlight covers the entire search spectrum of the Mac, especially Finder, which is the cornerstone of Mac navigation.
I’d think if I excluded something from being found in a search, but it was still being found, that this would be a serious flaw. So the fact that adding items to be excluded from a search result, are actually NOT showing up in a search result, that the system is doing its job as it was designed to do.
Companies are always evolving their software in part due to customer feedback, so I’d use the link that was posted earlier to give your input. I’m sure with the tech available now-a-days, there is a solution for everyone’s preference. Cheers.