I've written about this before on Quora. Basically, there's like
a million reasons against conscription, conscription being
something that a country is supposed to impose due to abject
desperation as in the case of Israel and South Korea where the
threat is very real, substantial, serious and ever-present.
Otherwise, there's North Korea, where it's due to authoritarianism
and dictatorship.
I could empathise with Singapore in the 60s and 70s for having
NS, because back then, things were still turbulent. But now? A lot
of countries which used to have conscription have already abolished
conscription long ago, leaving oddballs like Singapore and a few
others clinging onto NS like it's the key to paradise. And I can
tell you, a lot of countries without conscription have similar
population sizes as Singapore and yet more land and resources to
protect - yet they didn't put their citizens out there like cannon
fodder.
You can easily search Quora for all the reasons you can possibly
want against NS, plus all the desperate reasons for NS.