First of all, we do not practice Christmas even though we've left WT/JWs behind. We just don't need it.
I think former JWs that choose to celebrate Christmas don't give a rat's ass about "spirit & truth" of the foundations of the holiday. Christmas is no longer a "religious" holiday as it has been hijacked by secular society including non-Christian cultures. Only a very small percentage of celebrants are "glorifying the baby Jesus". No, the vast majority are enjoying time with family & friends. They are reaching out to friends with small gifts or even just a note/card to stay in touch and reconfirm their friendship. It's just too late to "put Christ back into Christmas".