The first thing I would note here is that this is an example of dense literary theory jargon and could have been written much more clearly. Basically, it is part of an extended scholarly debate about how to use postcolonial theory in analyzing Singaporean poetry.
It seems that what the author is trying to say, translated into plain English, is that many Singaporean poets address issues of nationalism or Singaporean identity. While other literary critics tend to interpret Boey Kim Cheng as also focused on the same issues, in fact, they are wrong in doing so.
The next claim Poon makes is that many critics think that when Singaporean poets write about travel away from Singapore, they are really talking about other places as veiled commentary about Singapore. Poon is arguing that when Boey Kim Cheng talks about travel, he is actually talking about a journey of self-exploration rather than about Singapore and also about the process of writing poetry.