Well, if that sort of thing were the be-all, end-all of religion or politics, then yes, there'd be little to no significant difference between either of them. As it stands, both are significantly more complicated than what you're describing.
While I disagree heavily with your conclusion, your observation that led to it is accurate: people tend to gravitate towards others of like-mind, where they all tend to agree with each other with little to no questioning. That's natural human social behavior; like the other great apes, we're a tribal species. Most non-indigenous Americans have long lost whatever their tribal connections were, and so we seek out other "tribes" to identify with, whether political or religious in nature, or even fandoms.
I don't know to what degree the term "tribalism" can apply to this behavior, since the term has a few different references, but it's the most self-descriptive term I can think of for this kind of behavior. Perhaps without realizing it, you're also exhibiting this behavior right now, by calling for others to be part of this "5% Tribe", and making that sound appealing by using popular phrases like "fight the good fight".
Thing is, this isn't inherently a bad thing. It's not at all a case of 100% blind, unquestioning tribal loyalty vs 100% cowboy individualism. As always thus far, the only thing in this world that I've seen which is truly binary, is binary itself. I honestly feel like pure cowboy individualism is just as destructive and scary as pure unquestioning group-think.
Side note, climate change isn't so much a political matter as a scientific one. It just happens to be a politically unpopular observation (and one that I observe myself). Be careful of what you label propaganda: applying that term at widespread opinions that you disagree with can indicate the same dismissive political agenda that you're criticizing. While there certainly is a lot of propaganda among certain ecology activists, that doesn't automatically make climate change itself an unreality. After all, there's plenty of pro-college propaganda out there; does that mean college itself is inherently bad and should be avoided?