It's a cultural thing

So we can all grumble about it on Lemmy.

There's any number of reasons. They might have a friend who uses Reddit who sent it to them. They might have replied on Reddit, and also have thought it worth broadcasting to their shitter followers as well. They might browse Reddit on desktop but not have an account.

Seems like the part of this thread where we're depositing gripes, so I'll just pile on without being helpful or answering your question:

The shit is backwards. It's like hearing the punchline of a joke before the setup. Posts like this translate so poorly to screenshots