voice;
There could be several reasons for that, but the most likely possibility is to create a connection between the inmates and their captor. Marina itself is created in such a way to give a sense of comfort and security, and by having a Warden that displays positive human emotion and genuinely seem to care about the prisoners, it's easier to keep us docile.
Of course, it could also stem from its creators. Humans have a tendency to superimpose a personality complete with emotions to inanimate objects - for example, some people feel genuine emotional pain when their car gets damaged, not because of the loss of property but rather because they identify with the object. In fact, there's a condition called objektophilia where an individual feels sexual and romantic attraction towards an object. Contrary to sexual fetishism they view this object as their partner and not the means to an end to enhance a human sexual relationship.