Having read this thread to this point, it occurs to me that I have no idea what the word anthem means in this context.
A quick Google and Wiki suggests two primary meanings of the word.
An anthem is a piece of music sung by a choir as part of a religious service. My brief search suggests that this usage appears to be within certain Christian traditions and refers to the place in the service in which the music appears. Thus the same song as sung by the congregation (all those attending the service) would not be an anthem (in this definitional context) but a hymn.
The second definition is that an anthem is a symbolic song of devotion or loyalty such as a country's national anthem.
The adjective anthemic is a song that has qualities suitable for an anthem.
Here is the national anthem of Russia. This is an amazingly beautiful piece of music (turn your stereo up to very loud). I have no idea what the words are, but the music itself is emotionally inspiring and uplifting. Truly anthemic.
So, what does all this mean here? Well I wasn't yet sure, so I ran a search for anthemic rock songs. The first hit I got was for
this list of the 100 Greatest Rock Anthems.
Looking at the list, you can see how some of these selections might be anthemic, or you can see various interpretations of the word anthemic. For instance, number five on this list is Queen's We Are The Champions, and I can certainly see how that song can be seen by some as anthemic (although personally, it's not an anthem for me); it seems to have anthemic qualities.
I have no idea what usefulness this post has in this thread, and I need to get another cup of coffee, and the clouds outside the window are really amazing this morning; so, without having yet made a point, I'll end this post here.