It makes sense for fediverse instances to have very low SEO (search engine ranking) as the content is split up across many different websites and domains.
Moon
Sadly this is very common for small game developers (and even large ones) to move entirely to Discord to avoid paying or managing a dedicated forum
As someone who runs multiple email servers, this is exactly how it works.
Some email providers will randomly or purposely block emails I sent to them. I get arbitrary blocks or dropped emails on sent emails.
Many communities and projects have replaced their wiki's with Discord and this model is being adopted by more and more communities.
Gone are wiki articles, which are replaced by live chat with a terrible search functionality and interface.
For me, the problem is not discords real time chat functionality (e.g. like IRC).It's that communities are using it as their only source of information and getting rid of wiki pages and support forums.
There are many open source projects and communities whose documentation lives entirely in Discord. This makes finding information much harder as search engines don't have the information indexed so you resort to asking on chat and hoping someone replies or using Discord's horrible search functionality (it's very basic and has a poor UI)
They also announced it on their Mastodon, I guess OP didn't realize they had one.