As always, great article JW Facts!
Forbidding the celebration of birthdays and other "pagan" holidays is meant to isolate JWs from their unbelieving family and to strenghten their hold on their members. It is a tactic used by all cults. In time the JW's life revolves around his newly found "family" and he has very little or no time at all to spent with his "fleshly" family...he has less and less things in common with them while all the "love" he needs is found in the congregation. This love from his "spiritual family" is conditional to his attending meetings and following the guidance of his new "mother" - the mighty organization.
I have left the cult 2 years ago and I no longer have "spiritual" brothers and sisters...and since I was a JW for 50 years, all my unbelieving family are now strangers to me because I never showed them the natural affection loving family members show each other...I am sadden by the fact that I will not have enough time left in my life to make up for the lost time and to regain a love I traded off for "conditional" love from cult members.