Why will only the front take down pin let go on this joke of a gun..or what is the common factor for those that have seen it before??

An old friend asked me to shoot his AR as it was not grouping & he just had shouder surgery...I was not expecting for him to hand this over. The mount is clearly an obvious issue as the scope moves with even slight pressure. All I wanted was to check bolt/lube before I shot and have no intention of further disassembly.

I have no idea where the appeal is for a plastic AR but rear pin will not clear. Gonna start saying no when cheap is clearly the objective.