Why transpeople specifically

There is a major push on the right to deny trans people rights and medical care. This article was intended to create outrage among them, as it relates to two groups who are popular to vilify: trans people and illegal immigrants, with an implication of wasteful spending as well. Rather than focusing on the benefits of public health care for most people, it singles out minority groups who the author portrays as unworthy of receiving it.

isn’t ‘infirmed’ an old time slur for disabled people?

My understanding was that infirmed just means people who are ill, however looking it up just now it evidently has implications of being feeble/weak/elderly that I did not intend.