What appears to be a tongue-in-cheek social media movement to mark June 29 as a day to celebrate heterosexual pride has become one of the day’s top online trends. Hundreds of thousands of tweets have been sent Wednesday with the hashtag #HeterosexualPrideDay. The idea of such a day has outraged many. One of the top responses comes from British comedian Dapper Laughs, who rhetorically asked on Twitter, “What’s next, #BreathingAirDay?” Others have flooded the hashtag with gay pride memes and other mentions of support. …