First and foremost why do they term anything against them as Poison?
If a poisonous apostate thinking can wreck your faith, sorry brother, your faith is very weak and without any foundation.
How do we determine its poison? What if it’s a life saving medicine? You need not taste anything to check out a Poisonous thing but there are a million other ways to determine if it’s a Poison or a life saving medicine.
Nobody can poison us NOT to believe that the sun or the moon Exists. If that is so, why does an argument against God or the WT so powerful and devastates faith?