Cognitive dissonance is mental process where people hold on to what they want to believe even when presented with overwhelming evidence to the contrary.
The idea that individual personal action is a measure of commitment is very much a conservative idea. This is the every person for them self attitude that has gotten us into so much trouble.
Democrats and progressives understand that collective action is the real key to change. We must act together in concert to achieve broad improvements in our society and environment. The actions of a single individual, either though choice, or necessity make very little difference providing that individual is contributing to the overall solution.
In answer to your question, what you are told to perceive as indicators of a lack of sincerity, is just another means to manipulate your emotions and create cognitive dissonance , so you will continue to choose to ignore the evidence. This manipulation is done to maintain the illusion that individual action and responsibility are the only way to make the world a better place. While individual action and responsibility play a small role, in reality the promotion of these as the highest ideals are a means to maintain the stays quo.
The easiest way to defeat an enemy is to divide and conquer. If people are unwilling to act collectively they are already divided and easily subjugated. After this is accomplished the key is to maintain the illusion of freedom and an improving way of life. People have a very short term perspective, so it is easy for them to not notice how much is taken from them over the course of 10 or 20 years.