Why are some people so afraid to show that they have stereotypical nerdy geeky, interests?

dungeons and dragons, board games, video games, anime, magic the gathering, star trek, harry potter, cosplaying

if anything, some of the coolest people i met have at least one of those interests i mentioned
Update: as a black male, i noticed this in our community. we get shunned by other black guys as being nerds, *******, or sissys, if we are not cool enough
Update 2: i notice that as people grow up and mature, its not really the adult thing to do by judging others for their interests.
Update 3: i felt shunned a lot when i was in high school, but i it lessened a lot as i got older and met actual adults that didn't care about it
Update 4: @lili . i didn't say i thought all those interests were cool. i said that some of the coolest people i met had at least one of those interests
Update 5: @lili,

and that is the problem with this whole "acting white" garbage. its a really closed-minded way to think. there is no such a thing as "acting white". you like what you like and race is irrelevant