"But Carrie Westgarth, a professor in human animal interactions at the University of Liverpool explains that there is no hard evidence to prove some breeds are naturally more aggressive than others" and in the context of the recent calls to ban XL Bullys, it's defending the breed by claiming it's not a problem.
I don't see how that's a defence of XL Bullys. I get that appeals to nuance are a way to downplay a particular issue, but I don't happen to see it in this case.
In that article you linked
"But Carrie Westgarth, a professor in human animal interactions at the University of Liverpool explains that there is no hard evidence to prove some breeds are naturally more aggressive than others" and in the context of the recent calls to ban XL Bullys, it's defending the breed by claiming it's not a problem.