Are the Arcturians on their home planet benevolent and perhaps unaware of the predatory behavior of their brethren here on earth?

Unfortunately, this is not the case. Like the Anunnaki, the Arcturians and their civilization has become heavily corrupted by spirit meddlers, and they have pulled away from their divine roots, and have suffered accordingly a degradation of their reach to the divine. The awareness and, in fact, the support from divine realm is increasingly limited, and they are moving towards the same plight as the spirit meddlers, in facing an eventual complete disconnection of life force energy from the divine, and then will perish as physical races. There may be spirit remnants who can make a parasitic existence happen for a time, but eventually all will perish, with the present trajectory that is well advanced now.