As part of ongoing efforts to simplify Reddit and improve Home feed personalization, the final steps to deprecate r/all are being implemented. All links to r/all will now redirect to the Home feed, following the prior removal of r/all entry points. Trending content remains available via r/popular.
Redditors on old.reddit.com, or those with settings that default to the old Reddit experience, will continue to access r/all as expected.
it’s also for the purpose of targeting ads. Even if you don’t have a reddit account the home page is still going to tailor the feed to subreddits you’ve visited in the past or your geo-location for example. this makes it easier for advertising.