The Buddha never called the "human realm" the "desire realm". The Buddha described the "human realm" as follows:
SN 56.61 The beings born (paccājāyanti) as humans (manussesu) are
few, while those not born as humans are many. Why is that? It is
because they have not seen the four noble truths.
AN 6.39 Bhikkhus, a god, a human or any other good state would not be
evident from actions born of greed, hate and delusion. Yet, bhikkhus,
from actions born of greed, hate and delusion a hellish being, an
animal birth a ghostly birth or some other bad state would be evident.
SN 56.47 Sooner, I say, would that blind turtle, coming to the surface
once every hundred years, insert its neck into that yoke with a single
hole than the fool who has gone once to the nether world would regain
the human state. For what reason? Because here, bhikkhus, there is no
conduct guided by the Dhamma, no righteous conduct, no wholesome
activity, no meritorious activity. Here there prevails mutual
devouring, the devouring of the weak. For what reason? Because,
bhikkhus, they have not seen the Four Noble Truths. What four? The
noble truth of suffering … the noble truth of the way leading to the
cessation of suffering.
Kamma obviously can exist in the form and formless realms, because these realms can be a type of becoming caused by craving, as follows:
SN 12.2 And what is becoming? These three are becomings: sensual
becoming, form becoming, & formless becoming. This is called becoming.
AN 3.76 "Ananda, if there were no kamma ripening in the sensuality-property,
would sensuality-becoming be discerned?”
“If there were no kamma ripening in the form-property, would
form-becoming be discerned?”
“If there were no kamma ripening in the formless-property, would
formless-becoming be discerned?”
Naturally, the bliss of the form & formless realms is impermanent, as follows:
AN 4.123 Again, there is the case where an individual, with the
stilling of directed thoughts & evaluations, enters & remains in the
second jhana: rapture & pleasure born of composure, unification of
awareness free from directed thought & evaluation — internal
assurance. He savors that, longs for that, finds satisfaction through
that. Staying there — fixed on that, dwelling there often, not falling
away from that — then when he dies he reappears in conjunction with
the Abhassara devas. The Abhassara devas, monks, have a
life-span of two eons. A run-of-the-mill person having stayed there,
having used up all the life-span of those devas, goes to hell, to the
animal womb, to the state of the hungry shades. But a disciple of the
Blessed One, having stayed there, having used up all the life-span of
those devas, is unbound right in that state of being. This, monks, is
the difference, this the distinction, this the distinguishing factor,
between an educated disciple of the noble ones and an uneducated
run-of-the-mill person, when there is a destination, a reappearing.
MN 111 Furthermore, with the complete transcending of the dimension of
the infinitude of consciousness, [perceiving,] 'There is nothing,'
Sariputta entered & remained in the dimension of nothingness. Whatever
qualities there are in the dimension of nothingness — the perception
of the dimension of nothingness, singleness of mind, contact, feeling,
perception, intention, consciousness, desire, decision, persistence,
mindfulness, equanimity, & attention — he ferreted them out one after
another. Known to him they arose, known to him they remained, known to
him they subsided. He discerned, 'So this is how these qualities, not
having been, come into play. Having been, they vanish.' He remained
unattracted & unrepelled with regard to those qualities, independent,
detached, released, dissociated, with an awareness rid of barriers. He
discerned that 'There is a further escape,' and pursuing it there
really was for him.