Actually, the Infiniti M is not a new car to infinti. Back in 1990 they had the m35, but it was replaced in 1993 by the j30. In 2003 they had an m45 but it was not popular at all, becuase people werent thrilled with the looks, it did have an impressive engine though 340hp and 333tq with a 4.5l v8. They are now re releasing the m45 with a whole new redesign and a 335hp engine with 340tq. They are also releasing a more tame m35 which has 280hp and 270tq 6cylinder engine.
This car is not supposed to be a copy of the bmw m series. It has been around for a while and, the evolution of this car shares no ties with the m series at all. The new m45 and m35 are based off of the Nissan Fuga.
There is no reason to get upset or mad at infiniti for this choice in name of their car.