Reddit sucks for many reasons and I refuse to use it, but as a software engineer, this hardly looks nefarious. That looks like a pretty typical event gateway in networked applications, which is used for all kinds of things to make a platform run. We have one in our application, and it's not used for any kind of privacy-invasive tracking. We use it for things like bulk data processing for things like userbase-level analytics (like, how many users are using this feature?), or for billing purposes for our customers (since we bill based on usage).

And calls to /api/* routes are absolutely completely normal for any SPA (single page app), and are required for them to function. There's certainly a technical argument to be made against SPAs in favor of more traditional server-side rendering (augmented by tools like https://htmx.org/ for dynamic content), which could be used to avoid these kinds of API calls (and, in fact, it's a model I'm very much in favor of), but that kind of architecture is far from the norm these days. The SPA model is the current (IMO bad, from a technical perspective) standard.

We have many reasons to shit on reddit and their behavior, but this honestly isn't one of them.