Admittedly it is a bit silly and we are anthropomorphizing them a bit, but it's helps keep us from being monsters in how we treat the animals, which in turn helps people sleep at night.

That is assuming people take it a little seriously and not just use the term as an excuse to justify being cold and ruthless in how we work with animals.

In the contrary you could argue, that humanizing them makes it easier to emotionally connect for humans. If that was the intention of the statue it works better that way. But I agree: if the statue would purely be for honoring the mice, it would be more appropriate to look like a real mouse.

i see you have never been a cult leader

To see if the ritual worked! How many times do we just pray and pray blindly? I mean, I don't, but if I were to pray I'd sacrifice some rats to track my progress.

Clearly you have never tried to correctly interpret the writings of cthulu.

Hum... The ritual rules require it. If you don't have control groups you will be labeled as heretical and people will exile you from the cult.