Many special characters aren't indexed simply because it would take more resources to index, store and compute results with them than without them.
Enabling indexing of few special characters probably wouldn't be that bad, but I have to keep in mind my limited resources. This seems like a very small use case that wouldn't be useful to very many people.
If I had resources to spare I would rather add support for searching characters of other languages, but I can't even do that right now.
Feel free to download the archive data yourself and index it however you want.