Take the atheist who says their deconversion was due to evidence yet that it is a lack of cognitive function and/or education that makes people religious. The Christian who claims to have freely chosen to have been Born Again but thinks all Muslims are brainwashed by and enslaved to The Devil. The Muslim who openly affirms the shahada without any claims of coercion as they sigh about how many people would convert to Islam if only they knew the truth about it.
Most people, religious or not, will claim to have selected their own belief system or lack thereof without compulsion or too much in the way of influence. At the same time, many (if not most) are ready, willing, able, and even eager to point out the environmental and other external factors that lead others to their disparate religious choices.
The atheist ignores the large numbers of well-educated, neurotypical individuals without cognitive disabilities who are religious as well as as the lesser-educated and/or cognitively impaired people who are religious. The Christian’s feelings of knowing The Holy Spirit would be called Satanic by the Muslims they criticize. Plenty of scholars of Islam are not Muslim despite their deep study of it; for that matter, I the ex-Muslim know more than a lot of Muslims do about my former faith (and plenty of Muslims know more than I do). No one can escape the influence of others and the world around them.
If you zoom out from individuals to consider the societal-level statistics, it is quite readily discernible that all the insistence on specialness means almost nothing. While people’s understanding and practice of their religion certainly tends to change over the course of their lives, the fact remains that the staggering majority of people live and die beneath the banner of the religion that they were taught to believe and/or that dominates their society.
This is despite the claim of Pew’s 2009 “Faith in Flux” publication that “Americans change religious affiliation early and often”; what they actually mean is “Americans tend to rotate between different flavors, denominations, and/or churches that are Christian.” “Church-shopping“, if you will, rather than anything more radical or surprising.
It’s clear that people do change their worldviews and/or religions. Given the low percentage of people who do in definitive fashion when it comes to the latter, I don’t know if religion is as freely-chosen as many might argue.
Anecdotes, statistics, and thoughts on this matter are both welcomed and encouraged.