Point out the irony in someone criticizing the alleged misleading of children about the "real meaning of Christmas" when the birth of Jesus, which is often associated with the holiday, did not actually occur in December or the winter season.
There is something ironic in the guy making an ass of himself because parents are "misleading" their children about the "real meaning of Christmas" thinks that meaning is the birth of Jesus, which didn't happen in December or the winter at all.  The early Christian church grafted Baby Jesus onto pagan holidays gentile converts to Christianity wouldn't give up now matter how many idiots like this clown shouted fire and brimstone at them.  Quite honestly, going to see Santa, a much debased stand in for the original scary Germanic deity who roamed the dark in midwinter with his army of the dead, blessing the good and doing unspeakable things to the bad is probably more in line with the "real meaning of Christmas" than listening to some idiot scream vapidly at a mall.