I think of this whenever I see the (many, many, many) examples of people who latch onto an abstract philosophy, then proceed to drive it into the ground without a hint of skepticism or devil's advocacy as they try to apply it every aspect of the world around them. People can become so enamored of an idea that they'll go to great lengths to warp their view of the world to conform to that idea, rather than update the idea based on what they see around them. Religious fundamentalists are easy targets here, but I'm thinking more of the extreme devotees of the various political perspectives.

Frequently these ideas/philosophies/etc. are very good ones, but when the philosophy becomes so enshrined and calcified that it ceases to evolve, it can become something that might guide you near the truth but prevent you from ever actually attaining it.

This is actually what I think of every time someone defends RMS by citing his consistency over the years. Without getting into the rightness or wrongness of his beliefs, his consistency is not a virtue. The flip side of this is the monologue in Diamond Age about hypocrisy- the tendency people have to use an example of apparent hypocrisy or inconsistency to discredit everything a person says or does.

TL;DR consistency is not necessarily a sign of truth and hypocrisy is not necessarily a sign of falsehood. Neither the world nor the minds of the people in it are perfect, so neither perceived consistency nor perceived hypocrisy are 100% accurate indicators of truthiness. Nothing absolves us of our responsibility to think for ourselves and maintain a healthy skepticism about the world around us at all times.