I have no idea why they are publishing pieces like this, and it’s objectively false. Mastodon had over 60,000 sign-ups in the last week, and my feed is as busy as it ever was. It went from like 4 million when I signed up less than a year ago to over twelve million now.
Here is an example for searching for “cats” with academic turned on. It’s not just .edus but it’s definitely part of the weighting. Nature is usually the first hit obviously.
You can also make custom searches with parameters and link easy access third party buttons. I did one for Google shopping for instance.