That presumes on the part of the person sitting in judgment of the designer that they know better and more about how the object should have been designed just by looking at it than the designer did knowing vastly more.
Have we reached the place in knowledge of genetics that we can with certainty that we know all the possible functions of every last bit if genetic material that exists? We may have some grasp of what genes control physical features but what controls emotions, thought, will, decision making?
Defining the physical features and breaking it down to simply the mechanical only tells us about the physical mechanical part of the entity. It doesn't tell us what it really is and there's no way that I know of yet for scientists to say for certain that they plummed the depths of genetics and know all every possible function of eery bit of DNA in every creature.
Tell me then, what's the difference between a living body and a dead one? What makes a body suddenly cease functioning when it's structurally identical to the one minutes before it expired? And I'm not talking about long enough for decay to set in, that argument has been used before. I'm talking about a body that's alive one minute and dead the next.
“What makes a body suddenly cease functioning when it’s structurally identical to the one minutes before it expired?”
I’m not a doctor or biologist, but I’ll take a stab at this. The heart stops pumping blood, which means that cells stop receiving the oxygen they need to live. Then the cells start to die. That’s why we can keep people “alive” with machines after their brains have largely stopped working, even to the point of not keeping normally autonomic functions like breathing and the heartbeat, operating on their own.