During high school, I felt like I was the only one with such beliefs, and for the most part, I likely was.
No, you weren't. Nobody talked about what they really thought, and in the absence of a channel for discussing such things the thoughts become repressed. Over time repression creates either anger or acceptance.
These individuals who are now posting or “liking” christian related items & images on FB were certainly not religious during high school, and it boggles my mind how someone in adulthood can come to believe such supernatural nonsense.
Much like the friends I have on Facebook, a few things happened to them.
First, they are not sufficiently inquisitive about the world in which they live. They do not investigate other things posted to Facebook, but accept them as fact. ("It's on the internet, so it must be true because I know it must be true.") Because there are things happening in the world that seem odd, wrong or outlandish, they latch on to whatever explanation someone gives them, and often it is a religious explanation. Without validation that a non-god or non-religious life is possible, they slowly accept that god must be real.
Second, their lives now revolve around raising their children from infants through college, and along the way they need help. They have a need for day care, pre-school/kindergarten, regular schooling (public or private), extracurricular activities (music, dance, sports) and some adult interaction (potluck dinners, movie nights, camping weekends, etc). Who is providing that support system? Churches. Certainly there are other groups who provide similar services, but by and large churches provide most of those experiences in a single entity. It's easier to associate with one place that does these things than ten others.
Third, after becoming ensnared in that black hole of religious participation, they find that all of their friends are within that religious social circle. They don't have friends outside it, not much anyway. And, to dare leave that circle means that they dare leave their friends (or vice-versa). The thing from which they gained social support now has a stranglehold on their intellectual capacity and every day activities. They cannot imagine leaving the circle. They cannot imagine not being part of a group, their group, right there, right in front of them. The church successfully kills their capacity for change.
I guess if one doesn’t learn, keep and use critical thinking skills in adulthood (and we see an abundance of that all around us don’t we?), then I suppose that if they get “loved on” by some Christians and get lured into that sense of community, then it’s entirely possible, but I just find it so shocking, and sad. I want to let fly with the arsenal of material I have at hand, but FB is not the right venue for that (for me anyway). Boy I’d like to let fly on this insane page:
https://www.facebook.com/JesusDaily
So does anyone share my experience of seeing their old friends become hypnotized by christinsanity?
Yes. Daily. Especially daily if I go onto Facebook daily. I try not to do so. I attempt to limit my Facebook visits to 2-3 times each week because family expects me to be on there and communicate with them. Like you, I am assaulted with all of their religious crap (some family members and more high school classmates). I "like" photos that people post, but if the photos are of them participating in church activities, I won't "like" those photos no matter if they already have 72 likes posted. I "like" smart posts, but if the posts are jibber-jabber, I mostly ignore them. Every once in a while I will reply to someone that they may have their facts wrong and give them a link to some helpful information (Snopes is a popular place for that). I can only think of one time that anyone challenged me and they didn't get very far. When shown something contradictory, these people stop commenting on their own fallacious threads. I don't reply often to these kinds of posts to prevent myself from becoming the overbearing asshole for which I have the great potential to be. Perhaps one thing that helps is that my classmates often recognize me as being one of the smartest kids in class (so posted by a few of them on Facebook already
[1]), so perhaps there is a minimum respect level given to me because of my past standing. Just a guess. I'm also not afraid to admit that I don't know anything about a particular topic on Facebook. Perhaps that helps, too.
So, what to do about all of this religious pandering? Just keep doing whatever it is that you do. Eventually, over the generations the younger minds will become more liberated. It will happen. The fewer edicts of the "good book" that they are compelled to follow, the fewer reasons they will have to cling to it.