MOS on a Mac is every bit as Amiga like as a SAM running AOS 4.1 is.
Is MOS on an Efika considered kosher by your standards, and therefore "Amiga"?
Is that Apple logo the only dis-qualifier in your definition of "Amiga"?  Is a Peg running MOS and AOS not an Amiga?  I mean, if I gutted a Mac Mini, put it in a new case, removed all traces of "Evil Apple" and I told you it was running on a Peg or Efika, would *THAT* be kosher?  You wouldn't know the difference 

Really man, it's an Apple logo.  Don't lose sleep over it, lol.  Personally I find Apple to make rock solid hardware, if a bit expensive at initial launch.
MOS and PPC Mac's serve a very valuable and economical entry point into getting people back into the Amiga (or Amiga like, if you prefer) scene, whether you want to admit it or not.