OK, well if Sinestro loses to Batman then explain to me this:
Why is there not a single person in the world who can beat my Sinestro with Batman?
My Sinestro sucks right? And you think it's a winning matchup for Batman right? Then why is it impossible for my Sinestro to lose to a Batman?
If it was a losing matchup you would be able to find at least one person on this planet who could beat my Sinestro with Batman....
I could find some Aquamans to beat 16bits Catwoman, I can find some Martians to beat Pigs Zod, I could find some Sinestros to beat KDZs Superman, I could find some Zods to beat Revolver's Lex..... Etc. Because those are actually bad matchups
If Batman supposedly beats Sinestro, you would be able to find at least one Batman on this planet Earth to beat my Sinestro.. But you can't. And my Sinestro is not even the greatest