i understand it can be foolish but why is it שנאת חינם?
In some rare instances, it might not be. But consider
realistically someone who won't eat lubavitch schechita won't eat at a chabad house either
That you have people who don't eat Lubavitch shechitah at home, but then you meet them at a Chabad House where they tell anyone willing to listen how dangerous and blasphemous Chabadniks are in between bowlfuls of Lubavitch shechitah cholent.