Pride and Wrath's fight wasn't kept a secret.
How can it become a secret when almost everybody in the Qliphoth sensed their fight? Many soldiers got injured because of their fight, of course, word of it will spread.
If it weren't for Sloth's interference, they might's destroyed the entirety of the Qliphoth, and that's something that can't happen right now.
Greed, the one who had a hand in this fiasco, felt some level of responsibility. After all, he was the one who sent Wrath flying away, crashing into Pride's territory.
He may not have been the one who gave Wrath the idea to fight Pride but it was he who sent Wrath there knowing that something was wrong with him.
To Greed's defense, Wrath pissed him off first. Wrath destroyed years worth of research. Greed was having a great time discovering things about this world and Wrath ruined his fun so he punished him a bit.
