To me, it isn't necessarily that M has made a SUV, but the way they've gone about doing it. I don't think any of the BMW M loyalists here would be as upset if these M twins had come with the current V10 updated with the M-DCT gearbox.
As far as it being double standard is concerned, let me count the ways. BMW talked down about forced induction, high curb weights, awd, and automatic transmissions. Their own press material for the M5/M6 spoke a lot about this in unnammed reference to AMG, Jaguar and Audi. For them to go and do the same exact thing is a farce, a grand about face, a lie to many M loyalists. Thats why. BMW put themeselves in the position to be different, and BMW and their most loyal fans lived and breathed the M way of going about performance and ridiculed any other way of doing it (i.e. supercharging, turbos, awd, automatics) and now they've done the exact same thing. There is no way around or to gloss over that. A 7-Series doesn't fit the M profile, but an X5 does? BMW just sold out (and pimped the M brand) under market pressue from Porsche and Mercedes, simply as that.
These M SUVs are nothing more than extensions of their regular turbo V8 siblings. Just like what AMG used to do.
It is so funny to me that now AMG has a totally unique engine from the rest of the lineup in most of their AMG cars, but BMW is going back to what AMG used to do, modify and existing pedestrian engine. There is where the ire is among M loyalists.
If the X6/X5 M twins debuted an updated n/a V10 and the M-DCT gearbox this conversation wouldn't be nearly as protracted. That said I like the X6 M a great deal. It will still be a hell of a performer and the looks stun.
M