Problem Is is a very straightforward poem. You can pretty much get what the writer is trying to convey with a few readings of the poem. As a whole, the poem is a social commentary directed towards societal ills in the Philippines mainly overpopulation and poverty.
The title alone speaks for the poem. With the title, Cruz is basically saying "here's the problem with Filipinos today". The body of the poem then proceeds to rattle off these problems.
1. Impoverished Filipinos multiply so quickly because they have nothing else to do but copulate.
2. Poor Filipinos live in small houses and tiny spaces which are conducive to copulation.
3. Impoverished Filipinos have no money for movies, fancy dinners, and books. So they copulate. It's free and it's accessible.
The poem also briefly touches on a few salient features of prevailing culture among impoverished Filipinos - the love for noontime variety television shows and the practice of borrowing (never owning) books.
The last four stanzas offer a glimmer of hope that Filipinos (the ones who are aware of the problems of poverty and over-population) might be able to escape the societal ills discussed in the previous stanzas. There's hope. There's a faint light coming from the end of the tunnel.
Filipinos are like rabbits looking over from an overgrazed pasture to a greener one. They are staring and dreaming of someday crossing to the other side. This might be a reference to Filipinos dreaming of a better life overseas. It might also be a reference to a better version of the Philippines. One where there's less poverty and less children per family.