Who/which should change first, doesn't really matter, because
this will lead to a better or worse Singapore.
As you've said, the constitution is vague. Since it's vague, it
means either you can do it or cannot do it. Look on the brighter
side, you probably can do something because the constitution is
vague. On the other hand, if the government pursues, this vagueness
becomes what they deem as illegal.
Trying although may harm, more harm is done when nobody bothers to
try, because their words will become ultimate.
The government is not us, neither are we the government. However,
collectively, both form the society, and the core of a society is
her people. When people improves, so will the society. Top-down
changes may be effective, but bottom-up changes are more permanent
and flexible as we are not as restricted.