This is an interesting one, and perhaps I have an answer.
I think the "hate" comes from not understanding what McIntosh is best at. That is room flexibility. I've never had the luxury of having a dedicated stereo room, so I never could get optimum acoustics.
They even have test equipment at the plant to make their equipment more forgiving. McIntosh amps and preamps work the best in unoptimized rooms.
Let me explain. During my solid state days, I tried out a Rowland amp and compared it with my Mac amp at the store. The Rowland sounded quite a bit better with perfect setup at the store. I take it home and set it up in my living room--the Rowland sounded a lot worse. My wife, who has better ears than me and could care less about the equipment, asked me what was wrong with the stereo.
I put the Mac amp back in the system.
Frankly, I don't even want a dedicated stereo room. It is more fun to share the equipment with family and friends in a more comfortable setting.
I am sitting in my room with one of my systems, and it is wonderful. Is it as good as the best setups I've heard? No, but with the Jean Nantais turntable, it is very, very close. And I can enjoy it while I am working, like right now. I don't have to sit in a specialized room to enjoy it.
That is probably one reason McIntosh equipment is still quite popular.