Despite having been founded in 2005, the S-1 notes that Reddit is “in the early stages of monetizing our business and there is no assurance we will be able to scale our business for future growth.”
Did they seriously just say "although our company start 19 years ago, we only able to start figure out how to make money, and if you buy our stock, we can't guarantee our company will grow further and give you more profits."
Having data means nothing if you can't monetize it.
As you say, AI can already access it all completely for free with nothing more complicated than a web crawler. Long term, charging AI firms for access is not a viable strategy unless the law changes.
And they've been trying for years to monetize visitors through advertising and other schemes, and so far come up consistently short.
That data is valuable, but I'm unconvinced that it belongs to Reddit. They didn't create it.
I also don't believe it should be free/legal for someone else to come along and take all that data off Reddit. While it was provided to Reddit by its creators, they haven't consented for it to be used by another party.
How you go about stopping that, I have no idea. How you go about monetising Reddit, I'm not sure about that either. It isn't by claiming you own everything though. Yes, you own the platform. But not the people, nor what they post. And those are the things that attract visitors.
Using IP laws to legislate this could also lead to disastrous consequences, like the monopolization of effective AI. If only those with billions in capital can make use of these tools, while free or open source models become illegal to distribute, it could mean a permanent power grab. If the capitalists end up controlling the "means of generation" and we the common folk can't use it.