ANSWER:

This does not take them out of the fold of Islam but it’s sinful as Prophet salla Allahu alaihi wa sallam forbade us from imitating the disbelievers.

Does celebrating birthdays make one out of the fold of islam while knowing that the root of celebrating birthday is from some shirk origin(for example the pagan origin, roman origin or kafirs did it for pharaoh etc)? I mean, after knowing all the roots, if someone celebrates birthday following their whims and desire, does they become out of the fold of islam?