Wow. You are taking on the role of a
thought police officer here.
If you think guys are sharing their content just to please YOU you might as well be delusional. Of course
I cannot say anything about another person's intentions either but at the same time, if i had to guess, i would say in many cases it will be either or both of the following: The guy who shares his junk online is (a) proud of what he has and not afraid to show it, or/and (b) has an exhibitionist inclination.
If thinking of a male looking at his stuff or even wanking his peewee over it would make him feel uncomfortable, most probably he wouldn't have posted it online in the first place. Well, either that or he is plain silly.
From my interactions with Black men on this site i feel like the vast majority of those are actually genuine an well-thought people and do not fall into the silly/stupid category. So my guess is they can well live with the fact that some of those looking at their media belong to the male gender group.