I think it's most likely because the bar and the hardware was all made for the 8th gen (06-11) Civics and it just happens to still fit on the 9th gens. The mounting holes on the lower arm are probably different but Progress is just sending the same 8th gen package and hardware.
But yeah, stinks when you have to revise and get your own bolts during an install. Put washers and those nylock nuts on to make sure everything stays tight and you never have to worry about it. You know the nuts that have that plastic ring on the one end? They work great.
These things: