This is what one calls insular or myopic logic. Its quite common in arguing a point of view when the world one operates in is rather small. You tend to see this quite often expressed by religious zealots and old school working class unionists.
Here is how it goes - you cannot be coach because you never played the game yourself. Tom cannot be humble by nature because he lost his temper. Dick spoke to the village thug, so he has to be a thuggish as well.
In the wider world, one operates in the environment that one is given. Goh Keng Swee started the SAF but myopic logic would not have allowed it because he was not trained as a soldier.
Here is another example from the opposite point of view. Mother Theresa is humble, therefore others who do not act in a smilar manner cannot be humble. Only Mother Therea can be humble. The point is that these things are very much relative and subjective.
Here is another perspective - there was a well regarded fighter pilot and past member of the original black knights who most people regarded as highly intuitive. This guy however couldn't push a pencil to pen a few lines to save himself. So does logic calls for a leader to be picked from a limited pool or a leader picked from a wider pool.
GY is humble, approachable and intelligent compared to the cabinet. But he is no Mother Theresa. He is also no Al Capone.
Its also does not mean that I will vote in GY. I don't posses the same myopic logic that Yaw and F4s have. Its never a zero sum game. If the idiot Ling stood in a fight with GY. I will vote Ling in a heartbeat because I would love to see the PAP monopoly reduced forcing them to be more accountable, transparent and less regalistic and arrogant. It does mean that I love Ling, admire him, or love the way he walks.
This is the problem with myopic logic and this is the most popular one. In any argument, if a remark or POV favours the PAP but is against the SDP, the term "PAP apologist" will emerge. Here is another - protesting in front of parliament house means you are hero and those that do not know means that you do not have the guts.
If you want to bring down the PAP or force it to act as a responsible government, one needs to grow a brain and be real smart in engaging them. Know that the world is not black or white but shades of grey. Do read extensively, meet and speak to as many people so you can to get a close to accurate composite view. Avoid insular or myopic reasoning at all costs.