This is just my view on the whole thing:
Angels do get bigger than some cichlids such as multies, rams, apistos, etc.. However, they are smaller than soooo many more. Take Oscars for example, one of the more commonly kept "large cichlids." Obviously, there are larger cichlids than Oscars out there, but, not nearly as few are bigger than them.
Some consider them to be large cichlids because they have kept tetras all their life and this is a big step up. However, if you go on to the monster fishkeepers forum, and say your monster is an angelfish, I think you would be laughed off the site!
One last thing I just want to point out is that many angels are measured in height. The vast majority of this height is fins, not fish! I would be willing to bet that if someone showed you a picture of an angel without its fins, you would not say that it's a large cichlid.
Just my two cents.....like I stated in the OP, I was just surprised that not everyone agreed on this, so I decided to get your input.
Feel free to discuss or argue my point of view, this has been a great discussion so far