Headcanon: Since Keeny was so religious, I highly doubt she celebrated Halloween. She would claim it was the devil's holiday. During the Halloween season while Jon is younger, he brings candy home from school which this sets Keeny off and she'd send him off to the church to see the crows. ANYWAY because of this, Jonathan probably never celebrated Halloween and the first time he does so, it's for theatrics as Scarecrow. It isn't until then that he realizes he actually really likes the holiday 🎃
This is actually canon, at least the first part. The flashbacks in Scarecrow: Year One take place during the fall, and Great Granny Keeny actually does refer to Halloween as the devil’s holiday. Young Jonathan wanted some of the free candy, but she forbade him to dress up because she assumed he’d go out and cause mischief. The whole scene is really quite sad.
I agree with you though, Jonathan probably has some bad memories associated with Halloween and his childhood. It’s not until he grows older that he’s allowed to savor the spooky celebration.
