A question came up on a forum I frequent.
Is it Wrong to stray from specified guidlines within a path? Will doing so tarnish a given practice? Will doing so show disrespect to those that have "done the work"? Should we adhere to the rules? Conversely, does holding onto the traditions from maybe thousands of years in the past keep us from moving forward? Should we take what we like, what is of use, and discard the rest?
Here's what I think. This is an easier question to answer with religions like Islam that have a core statement of faith. If you believe that there is no god but Allah and Muhammad is his prophet, that's all you have to believe. The other Pillars of Faith are all about action. So whatever else you believe, that one statement is your criterion. As I understand it, if you're on board with that, you're on board with Islam. If not, you're not.
Religions like Hinduism, Wicca, etc. are much trickier. A hard statement of faith like that--while extremely useful from a perspective of creating and sustaining a cultural identity for the group--is difficult precisely because excluding what is "not us" from what is "us" is contrary to what many Pagans want to see happening. Which basically means that developing any kind of coherent cultural identity within the group is contrary to what many Pagans want to see happening.
Christianity is somewhere in the middle. There are certainly statements of faith ("Jesus Christ is the son of the One True God and he died to redeem us from sin" or the like), but because there are so many definitions with their own interest in developing a unique core identity (which means they allow and exclude beliefs or believers based on criteria of their own in order to keep a coherent definition of their group)... there is a lot of fuzziness there. For example, multiple schools of thought about the nature of Christ.
There are the Nestorians, who feel that Jesus the man and Christ the son of God are effectively two different essences, even though they're centered around one guy and one name. Catholics are obviously not down with this (since whether the Virgin Mary was mother to just the human nature of Jesus or whether she birthed the whole kit and caboodle is kind of an important disputing point for them).
What I'm saying with all of this is that there are a lot of Muslims who meet the clearly-defined criteria set out by Islam, and are therefore justifiably defined as Muslim. There are Muslims who fit culturally but may not believe in the Shahadah. Islam has an easier time defining one as Muslim and one not than traditions like the various Pagan groups.
My personal feeling is that traditional groups are including and excluding certain beliefs out of a desire to maintain a cohesive identity. They basically just want to be able to know who they are. This isn't important to some Pagan groups, but out of respect to the ones that do place a priority on it, I wouldn't claim their name unless I fit their definitions. For groups that don't care who claims their name, sometimes I will when I'm intersecting with them.
So for me it's not about needing to define myself "correctly." It's about defining myself in a way that is respectful to the groups I may or may not be a part of depending on how much of a priority they place on being cohesive and how important it is to them to know who they are as a group.
So for me, it's not about an "Old Guard" needing to control their followers. It's about a group controlling their own identity, and if I respect them I'll let them do that for themselves if they need it. I won't take away their power to know who they are by clinging on to the group and muddling things up if the truth is that I'm actually something different from them.
That felt like a long ramble, but I hope I sort of got around to the point in there somewhere.
For other answers to this question, see the thread here.