Progressive taxation works primarily because those with broad shoulders contribute the most. Individuals contributing more to government income at the individual level does not have the same results, primarily because the benefits of higher taxation can only be realised if the policy is universally applied.
>I can easily afford more taxes. I don't mind paying my taxes
That person's argument is "I don't mind" and therefore taxes should be increased. My point is that just because that individual commenter doesn't mind, that doesn't generalize to everyone else who would be paying more in taxes.
In other words "I don't mind paying more" is an argument for you to pay more taxes. It's not an argument for me to pay more taxes, because I do mind. My comment is trying to raise this idea, albeit in a somewhat flip way.
Of course a policy universally applied will be more effective, but its silly to say its what people want. If people want to give more, they can.