ostentatious:
"characterized by vulgar or pretentious display; designed to impress or attract notice."
I'm sure he was trying to attract attention. Unless he (or someone else) just spent money on a shirt so he can stare at himself in a mirror with it, which would be ridiculous.
I mean, if you really want to pick and choose definitions to make your point, I won't stop you, but you've deviated pretty far from what you were originally arguing about.
I'm 100% sure that newspeed meant, nor incurred, no harm to the anti-brony with his actions. The so-called "problem" was almost entirely invented in the anti-brony's own head. It is completely irrational to characterize the sharing of opinions in a congenial manner as the shoving of stuff down one's throat. When an idea or tool works for a person, they naturally want to share it with others. This is only bad if it gets to the point where someone will force their ideas or tools onto another person, or, more likely, when someone will look down on the someone else for not corresponding with their ideas and tools. In this situation, the only person who's looking down on someone else is sir anti-brony who deserves much worse than five tabs of playful little ponies.