Most likely because it is of the heart condition, not the fact that he had it before he got the insurance. Like organ transplants on someone with late stage cancer.
I now see that the pastor refused to get Obamacare, because he didn’t want to pay the monthly premium. This story was about his “non-Obamacare” policy not covering this treatment.
The pastor now sounds more like a idiot to me ... than anything else.
A pre-existing heart condition should have no bearing on treating someone for cancer. Unless the said treatments would cause his heart to fail. We have no indication of this.