Walter Woon made a case as to why there is a constitutional flaw or pitfall in the position taken by the government. However, the fatal flaw depends on one's interpretation of how the govt has framed their position, in particular to the direction (if any) given to the Attorney-General.
Tommy Koh agrees that 377Ashould be taken out, but notes social and political concerns or considerations.
He frames the SG government's position as one of compromise on an difficult issue.
Yes, the govt is trying to walk the middle ground between the conservative and the more (let's call them) "progressive". This seems like a good compromise. Keep the law on the books to show solidarity with the conservatives, but don't enforce the law to avoid alienating the LGBT community.
The constitutional argument by Walter Woon is an academic argument at best. Even if the govt did not tell the AG not to enforce 377A, it would still be (almost) impossible for AG to enforce the law. In fact, the reality of the situation may well be that the AG might have advised the govt that the law would be unenforceable. And instead of taking the laws off the books, the govt might simply have framed the situation as they have: 377A is left on the books to reflect conservative values, but as a "compromise", the law will not be enforced.
Too clever for their own good eh?
Yes. Too clever.
What has happened though is that at least one conservative religious - Lawrence Khong had chosen to interpret (reasonable interpretation, I might add) that 377A means that the official position of the govt is that homosexual sex is wrong, is an offence, is a crime, is punishable under the law.
And then, Khong claim that his support of the "wear white" campaign, and his anti-LGBT statements/positions were simply to "defend the official position of the SG govt".
The SG govt has painted itself into a corner.
By keeping 377A on the books, the govt defended their decision as moving as fast as SG society is prepared to move. However, in doing so, they have, as Khong has put it, established the official position of the SG govt - that it is a reflection of conservative SG society.
The govt's "official position" is a compromise, and an untenable compromise at that. Khong has shown how vulnerable that compromise position is to be "hijacked" by the conservatives (religious or otherwise), how easily they may be used by the conservatives.
The compromise position has become a compromised position.
The SG government has resisted all the arguments from the LGBT community about how keeping 377A is discriminatory (or incriminatory?), by insisting that it is merely a reflection of societal mores, and there would be no active persecution (or is it prosecution) of LGBT.
But the govt's fence-sitting position can be used to persecute (if not prosecute) a campaign against the LGBT.
That is the fatal flaw of sitting on the fence on this issue.
It may be that politics is the art of negotiation and compromise, but sometimes politics is also about doing the right thing, leading people even when they are not ready. Or especially when they are not yet ready.
The alternative is to sit on the fence, uncomfortably, and be used by the unethical.