@ouij@tambayan.us
IMO, I gripe that the protocol is not beautifully designed at all :)
Setting that aside, though, generally when you search for a hashtag through your home account/instance, the instance doesn't search all of fediverse for it, but only searches through the limited number of posts that have happened to be shared to that one instance that you're on.
That really limits the horizon of content that is available for it to show you, but it's how the system was designed to function.
To put it a different way, each instance only subscribes to feeds that its users have expressed interest in, and so each can only sort through posts in those limited feeds. That's what you're seeing, the window that your particular instance has on the larger network.
@ramin_hal9001@emacs.ch