A nameless member

Answer: This could start getting metaphysical but ultimately it's semantics. An android is a humanoid robot. A robot is "a machine capable of carrying out a complex series of actions automatically". A machine is "a physical system using power to apply forces and control movement to perform an action". Note none of those definitions specify metal parts, or even being artificial. Human beings are machines, in the same way that human beings are animals, in literal terms, we're "just" biological machines, but we tend not to think of ourselves as such, because "human" is a more specific definition, and people like to feel that humanity confers a higher status of sorts. So it boils down to us vs. them, really - despite all of their many human traits, a lot of humans don't want to be conflated with replicants, so different terminology is used. There's also an argument to be made that as with a lot of dehumanising terms used in the present day, calling them machines helps to justify mistreatment, even though the replicants are just as capable of life and thought as humans are.

Answer: The replicants are indeed androids/machines; like Terminators, they are made to look human by adding human parts, such as skin and blood and even organs ("surrounded by living tissue", if you will). Unlike Terminators, however, they are not programmed simply to kill/destroy humans...they are simply "upgraded" versions of humans, who like all of us want to live with freedom and self-actualisation.