Here's better quality video that shows the actual pitch. The announcer suggests that Young may have thought the pitch was high, but I suppose that he thought it was outside. It couldn't have been a real bad pitch; in fact he may have been called out on his checked swing. To my eye, things look fairly calm until Young appears to be saying something to the umpire as he walks toward the first base dugout, and the ejection follows emphatically. I'm hard pressed to see anything obviously wrong with the umpire's call or handling of the situation.
http://www.minorleaguebaseball.com/app/index.jsp