This is crap. The atheists did not put up atheists holiday displays, they put up as far as I can tell anti-religion displays for the holidays. How wonderful of them. This does not excuse the vandalism, but it takes two sides.
I mean really "Religions are all alike -- founded on fables and mythologies." is a wonderful holiday message. I mean "Happy Solstice" is OK, but the other was just wrong.
The nativity scene is just that, a holiday tradition. The fables etc comment was the exact opposite and no more than an insult.
The atheist who did that is a childish moron as well as those who vandalized said signs.
PS: In the end everyone lost. Good job asshats!