I think this story contains some amount of poor judgement, but not nearly as much as the tremendous amount of tragedy here. Based on the video, it would seem that while each person could've been more prudent, nobody acted too out of line.
Some tragedies happen because Hashem wanted them to, not so much because anyone is at fault.
The yungerman sought to do a simple 3-second walk through, not thinking that it was anything to be concerned about. Keep in mind, that he likely does not read Mishpacha Magazine or peruse DDF, so he likely does not realize the super-sensitive mentality that exists now in these matters. The mother saw something that looked in her justifiably-sensitive mind as a travesty, and as Rabbi Lankry pointed out, she is within her rights to freak out.
I don't think anyone can really point at any of those parties and declare that they are deserving of the nightmare they fell into. On the other hand...
Someone once asked a rov to give insight into a famous argument between two prominent gedolim. (I think it may have been the Satmar Rov and Rav Moshe Feinstein.) The rov answered with a clever quip: If you look in Shmonah Esrei, you will see that although both gedolim are in the right - one is the "הָשִֽׁיבָה שׁוֹפְטֵֽינוּ" and the other is the "עַל הַצַּדִּיקִים" - it's the ravel rousers who come in between them that are the "וְלַמַּלְשִׁינִים".
The yungerman - poor judgement and all - did not intend to cause any harm. The mother was responding with her natural instincts. But the media, which just needed to stir things up for their bottom line, is the וְלַמַּלְשִׁינִים that are exacerbating the situation IMO.