As the article points out, Lee Kuan Yew did not believe that democracy meant that his (or any other party in power) should also help opposition parties politically thrive. While such political philosophies can be abused by authoritarians (and Lee was an authoritarian) in a democracy, I do see the wisdom in it. For example, Nehru - India's first Prime Minister - invited even some opposition leaders into his Cabinet as his party got an absolute majority in the first election post-independence. That was a rare departure from the convention of a Parliamentary Democracy, where only members from the ruling party or coalition form the Cabinet. Nehru however wanted to promote democratic values in India and since his party didn't really have an opposition, he invited some into the Cabinet to ensure their voice would have prominence in the media and the public. But he later abandoned this practise because the political ideological differences made this untenable in practise.

I have no idea and probably not, but it is a bit more complex than that. There isn't any particular rule saying that the only functional democratic model is multi-party democracy. One could imagine a successful democratic model with one party allowing diverse internal factions, for example. It is really hard to get a read on China, but their success raises some interesting questions of how exactly their internal party decision making is set up.

That being said, I would assume that a one party state isn't very democratic. It'd be an unstable democracy.

Did you know Philippines adopted American style democracy and were much more wealthier than Singapore and other Asian countries?

How do you think Philiippines compare now to Singapore as a result of its "democracy" ?

Competitively authoritarian, so, democratic.

If Singapore isn't a democracy then the U.S is a dictature.