I never said it was inappropriate to wear in real life, but that people should consider that maybe, just maybe someone might not feel comfortable as an adult wearing it.

And no, I'm not exaggerating. It's quite obvious that memes are breaking out from being an "in-joke" and becoming mainstream. It's not uncommon to see them being printed on shirts, and even advertisement(Comedy Central now adapts all the Futurama memes into their advertising). Hell, success kid was used on billboard advertisements for a while. And what you said is exactly what I was saying... they're being adopted into mainstream culture but for the Average Joe that encounters it doesn't know what it really means because it's been butchered by marketing and such at that point.