It’s a poorly written article, IMO, on what they are truly trying to report;
One sentence says the DOT “views a limitation based exclusively on breed of the service animal to not be allowed under its service animal regulation.”
And the very next sentence “Airlines are permitted to find that any specific animal, regardless of breed, poses a direct threat,” according to the agency.”
So basically it’s not allowed, but the airline has the right to deem Pit Bulls a threat and the entire compliance is voluntary anyways