Coaches don't know the rules?

[referee99]

Boys JV game last night. Team A ball in their front court, passing among teammates. Ball tipped by B1... going out of bounds... B2 bats ball towards Team B basket. Ball is deflected off of A1 (while still in Front court) and goes into Team A's back court. A1 then retrieves in the back court. Official (me) calls backcourt violation.

Coach and fans go crazy. Everyone saw the bat of the ball by B2. Coach wants answers. I tell him I'll explain it later.

At halftime, discuss the play with partner, the Var official who was watching, and the 2nd Var official that didn't see it but was in the office. Partner and Var witness are trying to sort out why it was backcourt violation. They are not quite getting it. I sum it up for them: "Team control. Last to touch in FC, first to touch in BC." Strangely, they are still a bit confused... one mentions that the coach was pretty adamant.

I suggest that the coach doesn't know the rules here... and mention that, "Look, if we (I guess that I was implying "you guys"), with all of our training and rules knowledge/study are sitting here trying to sort this play out, how the heck is a coach supposed to know this?"