Lal:All jati are undesirable. That is the explanation.
That is not how Thero explains it. At 23.02, he says “Can the likable and preferred (priya manāpa) nature of arisings (jāti) be considered as suffering? They are not. It is to this likeable and delightful nature the world-beings are attracted to. “Jāti api dukkha – jātipi dukkha)”
Here it is clear that he is saying not all jāti is dukkha. This is why he had to clarify that only Jāti api (disliked jati) is dukkha (23.15)
He also says the same for marana. We cannot translate maraṇampi dukkhaṁ as death is suffering, because not all death is suffering. He elaborates (30.54) “We welcome the demise/ death (‘marana’) of disliked and afflictive arisings/ manifestations/ things (jāti). That would certainly be a pleasant experience. How can it ever be suffering? We need to be truthful in understanding Dhamma, without deceiving ourselves”
Again he has to clarify (31.18) “Maranam api dukkha” means disliked demise/ death is suffering.