I know you're joking, but from that ostensibly gratuitous moment in the introduction it has been conveyed to the viewer that the doctor has a sense of touch in his cybernetic prosthesis. It tells us that the distinction of man and technology is blurring in their world, much as many Japanese experience their own identity and living, being overwhelmed by technology permeating ever more aspects of their daily routines and selves, and the doctor's close relation to all of this is heavily accentuated in this gesture of molestation so many anime viewers have gotten used to seeing that many would not consciously notice the world building that's being done, only fully reserved for the attentive viewer, but still overt enough to gain traction in the mind of any young Japanese person whose everyday life and very identity as a human is encroached upon by the ceaselessness of modern advancement. But that's mostly just commenting on the prosthesis itself and its employment in the context of such an ordinary anime trope. The doctor himself is old, patriarchal, a figure of authority, and the ass-grabbing is a forceful gesture, an abuse of power. The symbolism here is obvious and ties back to what I've said; technology is an enabling tool that may be abused by those in power, for ends heinous or trivial. Our everyday is bombarded with these themes, of how we relate to technology, how authority figures relate to technology, how we are enabled and disempowered by technology, how the powerful may force our interaction with technology, how the feeble may use technology for escapism, to alleviate their troubled minds for a moment, like how a crippled old man would grab his young secretary's shapely ass. A Japanese person can relate to all these themes, they are immersed in them, and even if they don't realize it, their subconscious will contextualize what they perceive, and that interaction is where the show's Japanese-relatable tone and atmosphere is created.