This is only a wild guess on my part, but I wonder if there is a grain of truth in it:

In essence, what matters the most for the author is not the time when they were in Latvia, but the time when they were not. First, they hadn't been to Latvia, and after that they started the thread (however silly it may sound).

It's like they want to say, "I started this thread when I had not been to Latvia yet", but for some reason it doesn't sound good enough, so they change "when I had not been to Latvia yet" to 'before I had been to Latvia".