If I scream profanities at a parking meter monitor for sheer sport, I guess I have created a "physically offensive condition" for no legitimate purpose since he needs to be there to do his job. (?)

If I scream profanities at Crowley in my yard while he STILL NEEDS TO BE THERE, the same rule would apply?

Gates was within first amendment (bias and identfy yourself - but not protesting arrest) rights and Crowley didn't need to be there, unless he really feared social unrest from those Harvard employees standing around.

The good news, I guess, is that eveybody has room to maneuver into that group hug photo on the White House lawn.