What is the difference between a dude who insists that he is a woman and may (or may not, as see 'Jenner, Bruce') have the amputated dick to "prove" it, on the one hand, and a dude proudly flaunting his copious tats and piercings, on the other hand?
The thing about "body modification" is that it displays that one has a feminine (in the "toxic" sense) mindset. Those pathetic guys running around with their "sleeves" and "gauges" are not showing the rest of us what tough and manly guys they are ... they're showing us what pussies they are.
Think about this. How do men generally compete for the attention of others (and for social status)? How do women generally compete for the attention of others (and for social status)? Men generally do it on the basis of their acts, of what they accomplish; women generally do it on the basis of their bodies, of what they look look like, of how thay have decorated their bodies. This is why women spend a lot of time and effort drawing attention to their bodies (*); this is why everyone looks askance at a man who has obviously spent a lot of time and effort to draw attention to his body (**).
Now, one of the things about trying to draw attention to your body is that this works best if your body is beautiful. Women generally have it oven men in that regard; very few of us men look like David Beckham. So -- this being the age of post-modernist revolt against beauty -- if you can't be pretty, then be ugly (***): thus, the ever-escalating cult of "body modification".
So, pity -- and scorn -- the tatted-up dude, for he hates that God made him a man (and he refuses to be one).
(*) and get so very angry when:
1) the "wrong guy" notices the very body they have deliberately put on display;
2) the "right guy" fails to notice (or fails to approve either the body or that it is on display) the body they have so painstakingly put on display for him.
(**) and because everyone *does* look askance at a man who has obviously spent a lot of time and effort to draw attention to his body, those tatted-up dudes have to pretend that they are doing it for another reason, such as "to express my individuality" ... you know, similar to how in times past women *had* to have clothes totally unique to any other woman's. The point here is that even in the publicly expressed rationale for their self-mutilation, they display their feminized non-masculine mind-sets.
(***) and, in fact, *because* this is the age of post-modernist revolt against beauty, even if you are pretty, you'd better make yourself ugly; thus, David Beckham (and his wife).