I would go with you on there. For me the difference between materialist and spiritualist is there is only matter and no soul vs only the soul matter (and only the chosen ones have one).That is true for synthetics that were created. But this event implies that your society fully understands that these are not robots or AI, these are xenos that just uploaded their minds to machines. There is a difference, I think.
As a neutral on the subject, I don't really see why I wouldn't be able to give these species rights.