Yeah, Eridan blew up the matriorb after the fight, but no one seems to remember who instigated it in the first place.
And before you continue, I’d like to point these two panels out as well:
He wasn’t even talking to Sollux in the first place.
So before you pin all of the blame on Eridan (And I’m not saying he doesn’t deserve any), consider that Sollux was very much involved, as well.
Him destroying the matriorb had nothing to do with the fight though. He always intended to destroy it- that’s why he was so insistent on “helping” Kanaya with it.