I second Ducky on this. If you feel TGEA is the finale, then by all means, you can believe that. But you shouldn't say "it is the finale, it always has been and always will be", because in the end, your belief in what is the final episode is just an opinion. You can't state it as fact, because it is not fact. It is opinion. There's a difference.
The LBT series has no continuity. No order in which the episodes run. Not all TV shows have a set order. Anyone can come into the LBT TV series and decide what order each of the episodes should go, and they wouldn't be wrong; there's really nothing to say "this episode goes before this". This is why you can say TGEA is suitable as a finale while someone else may have another episode they prefer as the finale.
You shouldn't really feel obliged to say that you were wrong, no more than someone else should feel obliged to say that you are right. If someone else disagrees with you, you should accept it. And you shouldn't try to pass off your opinion as fact. There is nothing to really support your claim of "TGEA is definitely the finale of the show"; it's only opinion.
Which is fine. Like I said, if you really do feel that's the best ep to end the series on, then you are free to believe that. Just don't go shoving your opinion down other's throats and try to make people agree with you. You can argue why you feel it's the best, but you can't place it on a pedestel and say "this is absolute fact".
We all have different opinions, Bruton. You just need to learn to accept it and not worry if someone disagrees with your views.