My argument is very simple: as the general word to indicate classical music is basically an extension of the more orthodox meaning of classical music (art music of the classical period), it's clear the music of the classical period is the core of classical music.
The music of the classical period and around consists of determined compositional practices, which translate in a determined and recognizable aesthetic. @YusufeVirdayyLmao
wrote that the composers consciously wrote music in a determined aesthetic that they considered as "superior", therefore the aesthetic is a intrinsic part of the art music of the classical period, not a casuality.
When more composers agree about the value of a determined aesthetic and create different pieces of music with common denominators, is called a genre.
Now, what I'm saying in this discussion is that the so called "cinematic classical" derivates from that genre, the core of classical music. The definition of "classical music" of the world newencylopedia says that the music rooted in classical music, is classical music, and since cinematic classical in most cases derivates from the core of classical music, and not from peripheric forms of classical music, I don't have to define the boundaries of classical music to support my argument.
I think that @Aries
should stop listing exclusionary criterias, because there are not. The composers of the classical period and around uses their musical genre to compose many different pieces of music for different functions: some of them were more complex, some others were less complex. Some others were written for entertainment, some others for the religious services.
The different pieces, written for different functions, don't share so much between each others, except of the aesthetic. So, it's the aesthetic alone which define their musical genre.
If someone says that classical music was not used for "direct entertainment", maybe he forgets that Mozart wrote collections of minuets (which, I suppose, were used to dance) and Dvorak composed the slavonic dances.
Except for the aesthetic, what do the slavonic dances of Dvorak share with his symphonies?
So, if you want you can say that music for soundtrack written in that genre is not classical music, but it's not that the names change the intrinsic properties of objects. If you call "man" a boy, it's not that the beard starts to grew on his face.
If you refuse to call determined filme scores "classical music", they don't lose their intrinsic properties. They remain where they are.