I think most people have beat this point into the ground by this point - but the idea of Section 377A doesn't make any sense.
Politically, 377A is only avidly advocated for by religious groups. There is no major active non-religious group against its repeal, which technically means that 377A isn't defending any major opinion - it's defending religion against the state, which completely turns the Singaporean secular state on its head. Regardless of whether or not you think gay people should be able to engage in consensual sex, it should be agreeable that this violates the principle of separation of church and state.
Logically, the Section isn't enforced, so it's just there in name. This just means it's there to give comfort to religious groups and certain anti-homosexual people out there, which is not really what the law is for. The law is meant to protect as many Singaporeans possible from crimes while maintaining civil liberties and other factors, not to make a pastor happy.
The argument that 377A will somehow encourage gay behaviour makes even less sense. Considering that gay behaviour is basically overlooked, that means that it approximately will just keep the amount of gay people as a proportion of the population the same. At best, this will encourage more closeted gay people to come out, which isn't really the worst thing. This doesn't mean they're going to engage in naked sex on East Coast Park, this just means that the government acknowledges their equal right to consensual sex as everyone else.
And finally - morally - it is offensive. The law encourages discrimination against people who are inclined to like people of their own sex more than the other just because of a natural inclination. It's a quiet middle finger to people who can't help their natural inclinations, while reaching a helping hand to large religious groups who encourage this sort of discrimination. Isn't this a violation of the rights afforded to all Singaporeans? Put it this way - we cannot control someone else's sexual inclination, yet we're actively attempting to do so, while discriminating against them for something out of their control. This should be grounds for outrage for everyone, regardless of religion.
Section 377A is just an outdated section of the law that makes no sense. And we're better off getting rid of this horrendous stain before the rest of the world starts watching.