The lifetime rates of breast cancer in the US (most likely similar in the UK) are one in eight for women (vulva types) and one in 833 for men (penis types). So the female risk is 100 times the male risk.
Lumping everyone together into the same prevention/self-screening category hides that. But the nonbinary pals category actually consists of some (more than half, it seems) who face the 1 in 8 risk and some who face the 1 in 833 risk.
So doing the palpating of breasts is much more important for those who are female, though everyone should be aware of how their bodies feel and function normally so that they can spot differences which might mean that medical attention is needed.
I don't think the all-together-now type of inclusiveness is the best way of discussing something with such great differences in incidence, especially if it makes understanding the real risks harder for some groups.
What this shows to me, yet again, is that we need to keep terms for people of the two sexes in areas where sex matters a lot (medicine, fighting sex-based oppression, sexual violence statistics).