pioneer 4200 nex with idatalink maestro

So for all you audio techs out here I have a question. So I was trying to add a cable to be able to pass video from hdmi to rca and plug it in to the aux port in the back. That way I'm able to watch my phone in the front and back screens. Reason I'm wanting to use the aux as i have a front camera and rear taking up the video inputs already. I took it apart and to my surprise the idatalink data cable is connected to the aux port and I have no idea why?? after doing some research I see the stereo has an actual port for the maestro but these guys used the aux port. Ill post a picture. the plugs I circled in red are what I'm questioning. Should there even be anything plugged in to those 2 if I'm running the maestro?

 

@james@tech12volts any idea?

 

i do not deal in Pioneer as we had nothing but issues with them but I do not think that is correct . I think the installer missed the hole

 

Thank you