Can anyone give me insight into cultural attitudes towards it there?
Kenta Cho's games have been ported but I believe they are the only Japanese shmups I've seen.
Oh and there is Kobo Deluxe which is a gem.
Maybe there are sites and download links for doujin games but I can only read English.

Hopefully they will start to realize it exists as more doujin games are released on Steam's service.