According to the police report submitted by Baraboo PD, cops say the father was questioned by officers that night -- and in terms of a rationale ... they claim he told them he had some kind of personal history with superintendent Rainey Briggs ... the Black school official he shoved away.

Per the docs, obtained by TMZ, the dad told police he had "past issues with Rainey and dislike[d] him." He also allegedly said he didn't want Rainey to have the satisfaction of shaking his daughter's hand.

The cops go on to note that the dad was vague upon further questioning -- and eventually, the cops say they scolded the father about his actions ... telling him the way he conducted himself wasn't acceptable.

The father was apparently asked if he was remorseful over what he'd done, and the cops claim he said yes -- but only for his daughter's sake ... so, it sounds like he's still bitter over whatever beef he has with the superintendent.

The cops also note that based on their convo with the dad, they believe he'd planned to do this ahead of time. Anyway, the dad was ejected from the premises -- and the officer decided to issue a summons on a disorderly conduct charge.

BTW, Rainey himself filed for a restraining order and in the docs -- obtained by TMZ -- he does NOT get into personal history between himself and the dad. In fact, he notes that his relationship to the father is "Random" ... so on its face, it seems he was taken aback.

Rainey describes the incident in the docs, claiming the father said "you are not going to touch my f***ing daughter." Rainey says he pushed the dad away and told him to keep his hands off of him before they were broken up and the dad was whisked away.