i see a lot of people with a lot of misinformation 
if you are a singapore citizen, even if you have a passport with
one day left on it, the singapore authorities will not stop you if
you want to go.. you have a right of exit and entry into
singapore.. even with an expired singapore passport, as long as you
can show that you are a singapore citizen, you have right of entry
into singapore...
however, if you are going to another country, you have no right of
entry into THEIR country.. you are a foreigner to them and because
of that, you have to abide by their laws... if they insist on the 6
month validity, they have the right to not let you into their
country... heck! even if you have a brand new passport, they have
the right to not let you into their country.. and you have no say
in it at all...
the 6 months validity is some international law thing.. or
something.. everyone adheres to it... if the immigration fellas the
other side lets it slide, then it's their right, and your
privilege...
figure out the difference between rights and privileges... and it
all falls into place.. 