I had my location set. I have been *FORCED* to put a value in the birthday field. Why? what concern is it of anyone else? I don't like people gathering data that is of no use and no relevance. Recent events have shown how easy it is for data to get out. You may say my birthday is trivial - but it's the principle of the thing.
Unfortunately we can't do anything about this.
The location field has been set to a 'Required Field' but vBulletin includes the 'Date of Birth' field within this data set, so if you set one to 'required', then by default both are set to 'required'.
I understand that you might not want to show your DoB, but you do have the option to hide it, or if you're really cynical put a false date

.
The vBulletin software that this forum is built on is an 'off the shelf' package and we are unable to change parts of it.
I don't recall ever saying that your Birthday was trivial - in fact I think it should be celebrated annually with a HUGE party to which we are all invited - and now that you have to show a location, we'll all know where to come for the beer.....
Joking aside, I hope this answers your concerns.