First I'm not sure that I learned, or reasoned without the assistance of adults (who taught me how to reason) that Santa Clause and the Easter Bunny aren't real. I personally was told that they weren't real and then accepted that they weren't real, and moved on. But, for the record, I don't think Santa Clause and the Easter Bunny are in the same epistemic boat. Mainly because I've never seen any cosmological, or teleological arguments for Santa Clause, or the Easter Bunny. And also because I've never seen any arguements from evil for why Santa Clause and the Easter Bunny don't exist. I'm not entirely sure that I understand what "reason" is, nor am I entirely sure that religiouse beliefs are unreasonable; this is a huge epistemological question and I'm not sure I've found an answer to it yet; nor do I think a lot of so called rationalists, even though they are quite sure that they have. So, i'm not sure i understand your question.