He denounced his entire involvement with the production once the final film was released, saying they'd strayed too far from his original vision.

Good evening.

I would like to ask about one more long sentence:

He denounced his entire involvement with the production once the final film was released, saying they'd strayed too far from his original vision.

a) Is it grammatically correct?
b) Is the comma after 'released' OK?
c) How would you interpret the word 'denounce' in this context? Does it make sense?

For me, it looks strange but if I had to interpret it I would say it means that he announced the termination of his involvement in this undertaking (isn't it too late though, when the movie is released?).
By the way, this meaning can be found in https://en.wiktionary.org/wiki/denounce#Verb and https://www.merriam-webster.com/dictionary/denounce but what is interesting neither https://www.oxfordlearnersdictionaries.com/definition/english/denounce?q=denounce / https://en.oxforddictionaries.com/definition/denounce nor https://dictionary.cambridge.org/dictionary/english/denounce mention it.
The most straightforward interpretation could be that he simply strongly criticised his involvement, but it doesn't make much sense too since it is not his fault that other people strayed from his vision.