To be fair to the Catholic hospital, they'd also refuse the surgery to a woman comfortable with her female identity for want of a better term that doesn't get my post deleted unless there was a medical need beyond "I want" because it doesn't align with their beliefs on sterilisation.
That it's a transman is utterly irrelevant to them, it's still a functioning womb capable of sustaining life that isn't physically compromised by medical issues.
I absolutely don't agree that anyone should have more autonomy over a woman's body than the woman herself but that's an entirely different argument to whether the hospital are being discriminatory by applying the same standard to a transman as to a woman.
As an aside, it doesn't mention whether the Catholic hospital performs procedures on transwomen that would permanently alter their fertility...that would be far more relevant and comparable if suing on the basis of discrimination.