This might be too cynical, but I think they've been allowing this to "pad their numbers" when it comes to site metrics.

Huffman talked before Congress and said this:

For example, on average Reddit handles more than 750,000 posts and 6.3 million comments per day across over 130,000 active communities.

They put this on their blog:

Reddit 2020 By-The-Numbers:

• 52 million daily active users – up 44% YoY*
• 303.4 million posts – up 52.4% YoY
• 2 billion comments – up 18.6% YoY
• 49.2 billion upvotes – up 53.8% YoY

The problem with that is 25-60% of those comments are from the same spammers they've been allowing to run amok for years. The whole reason these guys can spam millions of comments per day is because Reddit removed rate limiting for moderators on their own subreddits.

I discussed it with an employee a couple years ago and they told me I shouldn't assume malice, just incompetence and that "rate limits are just an exceptionally dumb way to do anti-spam in general". Which sounds completely absurd and here's Reddit now adding a pretty harsh rate limit for editing comments because of spam.

So:

• Reddit created the spam issue by removing rate limits for mods.
• They've allowed spammers to make millions of comments per day for years.
• Rather than preventing it, they just hide it from the users.
• They include these numbers when talking about how active their site is in front of Congress and in their "Year in Review" blog.

I have no problem believing Reddit management is incompetent when it comes to a lot of things but how am I supposed to believe something like this isn't intentional when they make changes to allow it to happen, let it make up the majority of their site's comments for years, and then include the numbers in their activity reports?