Heterosexism?

I guess I'm not really keeping up with the latest.  I typed the word Heterosexism and there isn't even a spelling error indicator.  It is that common I guess.  What does that even mean?  I realize that guys and gals in lab coats have effectively convinced our college educated generation that the whole idea that sex ever had anything to do with procreation was a big, homophobic conspiracy.  Is heterosexism simply another way of saying that?  There are so many -isms and phobias out there, I can't keep track.

The article itself is from my Alma Mater, The Ohio State University.  The meat of the post is nothing new.  Basically liberals exploring whether or not humans are morally obligated to obey liberal dogmas.  In this particular case, it is the non-white, non-Hispanic, non-Asian, non-Native American Lives Matter Movement.  Though I do appreciate how deftly that movement is now being defined as a movement that draws attention to all minorities declared oppressed by structural evils.  It's just that the term Heterosexism threw me.   Someday liberalism is going to have to publish the official Dictionary of Liberal Terms.