This seems like a pretty reasonable way for a manga reader to handle it.
If you were wrong back then, before you knew the answer, you can be wrong again in the anime thread. If you predicted correctly back in the day, then you're prediction still stands.
Hell, sometimes, when a show is having an "oh shit" moment, I'll go look up what manga chapter it happened in, then go check out the thread for that chapter just to see how everyone reacted back then.