And the problem here is that excessive respect for specific beliefs may lead some people to rest weight to the possibility that someone may really be experiencing hallucinations.

I don't deny that plenty of psychiatric medication is prescribed without solid foundations (both about the patience's situation and the research behind the drug), and sometimes has negative consequences (I've had bad experiences with antidepressants myself), but not all forms of distrust are equally valid, productive or safe. Let's assume that the person at OP genuinely suffered a bad reaction to the drug (personally I think it's likely), even then there are still two possibilities: either A) They did mistake their internal trail of thought with an external voice due to religious interpretation, or B) They are genuinely experiencing hallucinations. If it's A, there's isn't a great issue with ignoring it, they're a fool but there are plenty of fools in the world*. If it's B, they likely have another mental health condition that requires identification and treatment, but excessive respect for irrational beliefs muddles the question. If the immense majority of the people this person interacts with share their beliefs, the chances that they'll confront them when they realize that they're speaking to someone that is not there will heavily diminish.

*You could still argue that someone mistaking their own thoughts with the voice of God can also become a serious trouble if they reach some dangerous belief, such as a form of violent political radicalism, but I assume that schizophrenia is far more likely to be an issue.