Looking back at the original mail, it seems like the main complaint is that the two packages were treated differently. The easiest resolution to that problem is to go ahead and remove node-autoprefixer. That'll solve the inconsistency.
How small is too small is a judgement call may be the FTP team member reviewing the package. Different people will not always make the same judgement. Unless someone can figure out an actual resolvable controversy, I don't seen any point in bothering other FTP team members with this. To the extent anything is being requested, it seems like it's infeasible (write down exact rules for what too small to split into multiple binaries would be and then have all FTP team members apply the standard perfectly). Scott K