Discord is bad because its forums are not world-readable, therefore not indexable. It’s very useful to the rest of the world to have conversations be public. The youngest users here may not even remember but searching Google in the 2000s before Facebook went huge and when forums were all world-readable, it was a different experience altogether. You could find somebody who was talking about your niche issue/product - no matter what it was. It was kind of magical. No matter what thing happened to you, you could be pretty sure it had happened to someone else and they were talking about it somewhere and Google would see it and point it out to you.
Not anymore. Everything’s on Facebook now and Google can’t see it, nor can anyone else - except Facebook. All that legacy knowledge just tucked away in Facebook’s data vault and essentially useless to anybody but Facebook, which makes it less than useless.
Algorithms are not universally good and helpful. They should be designed to boost engagement only in that they serve to find content you wouldn’t be able to see otherwise, not to boost engagement at all costs by feeding you things they think you will click on. It’s an important distinction.