One specific case? How about this one:

Gay Man Tormented at Work Then Fired for Being Gay Has No Legal Recourse, Court Rules

Or these eleven:

http://www.advocate.com/year-review/2013/12/18/meet-people-fired-being-lgbt-2013

Or these five:

http://williamsinstitute.law.ucla.edu/press/5-people-who-were-fired-for-being-gay-and-the-29-states-where-that-is-still-legal/

Those are just a few of the public cases I found in a couple of minutes on Google.

And let’s not forget that there are good reasons why people choose not to go public in such situations and that, in most cases, where discrimination is involved, the employer won’t be openly giving the reason.

It happens.

Maybe it never happened right under your nose, but it happens.