Let me clarify - why should we offer Meta leeway to implement such a flawed review system.
17 is a weird number but having a number is perfectly reasonable to me.
Requiring N distinct reports of a suspension reason would seem to reduce misuses of the reporting system.
The 17-reports threshold might have been found to balance type-1 and type-2 errors, as account removals are costly actions when made in error or as a result of reporting-system misuse.