Imagine the world as an endless building that constantly keeps building up, piling up bricks and building material.
Simple structures make the start, but turn to complex systems over time.
And even complex systems develop many branches that are hardly to survey anytime.
Experience gathers, information gathers, memories (both silent and actively present) gather.
That's why this process keeps happening...
Until someone might give it a closure through total destruction of everything that commits this process.
Everyone who would want to make an attempt for a change to human civilization or his own cultural norms should better regard it like that 'cause that's why past things and circumstances can't be reconstructed and rebuild the same way they once used to be. Ideological purity as desired can't be maintained over all epochs - simply because things keep changing. New things add, some things drop from the boat.
Purity would mean to regard these innovations with a mindset that doesn't suit making a judgment over these things, that's completely unable to do so, or it would mean to totally ignore it and by that ignoring the signs of the time, changes inside the building that constantly piles up.
So to say, it would mean to try to conserve a construct of circumstances and influences for all eternity, which isn't possible in a world that's subject and slave to a circle consisting of birth and death.
People that are responsible for the world of yesterday won't naturally exist forever, so their world and thoughts on it don't do so too. So also purity can't be maintained forever.
Wake thought and mind is what better controls the stream of ideology - 'cause it makes ideology keeping up to date with problems that appear and with developments that unfold.
This doesn't even mean a betrayal to a cause or club 'cause as long as the general path, the general thinking pattern, remains the same structure, it isn't like someone has left the path he has assigned himself to before. He just bows down to the process of how things work in general: A building that constantly keeps piling up, creating new structures here and there, dropping old styles, not continuing some of these new branches, continuing some of the old ones with new components.