You have evidence that a man being persecuted by the Catholic church, who was silenced and made to denounce his own scientific discoveries, claimed he was still a Catholic. Hmm, does that sound coerced enough?
Non-believers, pagans, Muslims, atheist, were always persecuted by the church. Some were raised, like for example Einstein, within a religion - or even Darwin - and never truly said "I don't believe anymore" but it's not to say they believed whole heartedly either. In Darwin's case, his wife, who he loved dearly, was very much religious, and from what I've read it would break her heart had he said he didn't believe anymore. Much as that is true for any number of people like Darwin or Einstein or Galileo who discovered certain truths about our world that the church disagreed with or went against their families faith.
We all have to keep appearances at times.
- Oni