Yes, his services were coerced, but in all this there's still nothing to indicate that the work was not the product of purely subjective expression. I can be forced at gunpoint to create an artwork and it could still be the product of purely subjective expression.
That's where you're wrong. Motivation is not what determines whether something is purely artistic or not. You can certainly be motivated as an artist to earn a living, as long as the work itself is not created specifically to be objectified and equated with a sum of money (i.e. to be sold in the marketplace). It's when the commodification of an artwork is involved in its creative process that subjective expression is undermined. Thus the difference between a true piece of art and a souvenir or a product.
It's simply contradictory how art is regarded as having subjective value but is also meant to be translated into something that has objective value in the marketplace. You can't have your cake and eat it too. In fact, this implies that art should be ideally be free. It's the services of the artist that should be paid for.
Also, this is not a way of differentiating art from non-art, whatever that means. Essentially, in order to retain full artistic integrity, an artwork has to be the purely subjective expression of the artist without regard for objective social concepts such as demand and supply. You can certainly make a living as an artist who is engaged pure artistry, but that is going to be very difficult and you might have to compromise at some point. Hence, non-professional art is still more likely to be pure.
This seems quite contrary to your original 'Art that is made for money is compromised' position. The former is clearly a judgement based on motivation whilst now you are talking about
means. Namely, art is only art if it is something created through the means of subjective expression.
What do you mean by 'subjective expression'? I'm having a hard time interpreting the phrase in such a manner that bars video games from status as 'art' but allows music, painting, sculpture, literature so on and so forth. On one level the creation of anything original is bound to be subjective; if it did not in some way involve subjective processes it could hardly be original. This does not, of course, preclude video games from the status of art. On another level the requirement 'true' art has to be
purely subjective seems impossible; it imagines the artist as an entirely closed system, with no inputs from social concepts. The Sistine Chapel ceiling is certainly based on external social concepts; It is based on the bible.
Frankly, I think your entire approach is wrong; You seem to presuppose that there is an
essential quality to art that determines its purity, how close it approaches bering 'art' ("essentially, to retain full artistic integrity..."). That there is a certain quality all art must share otherwise it cannot be called art. Given some art has more of this essential quality then other art, some art is more 'pure' then other art.
The problem is, no such essential quality is present and the clear boundaries of definition it demands are impossible. 'Essential qualities' and 'definition' is not the means by which words function, and art is no different. We only attempt to define a word when we already
knowhow to use said word; it is this use that creates meaning. We do not have something essential that links all instances of a word's use together, and nor do we need one. All we need is a family resemblance between the usages of a word. We do not need a single fibre running through the usage of a word but rather overlapping fibres between usages.
Consequently to say that something is not art because it is not art because it does not have the essential quality of subjective expression is to misunderstand how we use 'art' in language. When looking at the Mona Lisa or listening to Mozart we do not consider whether these pieces are 'subjective expression' before appreciating them as art. We intuitively see they bear familial resemblance to other works of art and thus automatically consider them art.