And some people are just taught that it's flat-out wrong, and a blasphemy to their faith... and that kind of thing can be a ridiculous barrier to overcome.
I agree about things being taught early on in one's life being very difficult to overcome. But it can be very liberating once it's done.
My folks were Christian Scientists, so doctors and medicine were the "blasphemy to their faith," along with much of any acknowledgment that one could get sick at all, let alone actually be gravely ill or even in pain.
Every time a Christian Scientist falls ill, the strategy is to not only pray over them, but also to cause them to "come to the Truth, for they are convinced of a lie, the lie of any imperfection in God's Temple, the human body."
..etc. Like homophobia, I bought into it; everybody who did not believe what I believed was awash in a Big Lie.
Often there is a mixture of insight and outright twisted logic in their thinking.
One day I asked my Dad where this lie came from if God made everything perfect. "It does not exist," he answered, "it is an illusion. Dark does not exist, it is merely the absence of light. Lies are the same way, merely the absence of Truth. Once in the Truth, we see and are healed."
"Where did the illusion come from if God made us perfect?" I asked, "why do we have to keep finding our way around and out of things that don't exist?"
The look on his face helped turn me around and it also comes to mind when I'm listening to somebody talk about "blasphemy" whether in reference to gays or atheism or whatever.
They simply have a mindset which they feel safe in, no matter how patently absurd that mindset is.