Appreciation of music should be subjective
Analysis of music should be objective
Music has always had context; film music is no different, but Opera is intended for a stage and demands consideration of the story, Symphonies are intended a concert hall and Chamber music was, well, intended to be realised in an intimate setting.
This does not mean you cannot take an Opera and have it performed by a bunch of soloists in a concert hall, or that symphonies cannot be recorded. However, the intention with which the music was composed remains.
However, it may not matter to you - everybody appreciates music in their own way, and I often enoy listening to film music on CD. However, if I'm going to analyse it (objectively), I have no choice but to consider its original context.
With regard to errors, yep, craftsmanship does not appear to be a priority at the moment for a lot of successful composers in the film music profession. It's a shame but, as long as the music is valid in its context (supports the film, does not disturb me whilst I'm watching the film etc.) I can cope with it. As long as I'm intending to appreciate the film, rather than analyse the music. This is usually not such a huge issue these days, since the music is often so low in the mix (below the effects) that the intricacies of the orchestration are hidden, so in the auditorium at the cinema you often cannot hear very well how the voice leading is working. So in that context, it may not be a problem - subjectively.
It's all a matter of context, and for what purpose you are considering the music.
Feel free to disagree violently.