Actually, we should go after (through boycotts) those who fund those organizations.
I’d much prefer tar and feathering and deportation.
If the "world" wants to eliminate the public celebration of Christmas, we should be perfectly willing to a) make sure it doesn't get to benefit from any of the publicly promoted trappings of it like time off and b) withdraw from the retail participation of it (i.e. make gifts, concentrate on celebrating it more spiritually, etc...)
The people running the show in these places are going to continue to piss on our Christian backs and tell us it's raining until ALL of the beloved revenue it generates for them drys up and goes away.