You may know someone who belongs to your religion-sect, brought up in exactly same environment like you, taught by same teachers, read the same religious books but yet has different religious believes or practices than you; OK, may be slightly different but different, nevertheless.
Yes I have seen that many times. It does seem that everyone allows some kind of variations in his / her religious believes; perhaps to take care of his/her personal circumstances or to harmonize with some compromises in practical life.
Perhaps this is because religion, like most human matters, is not science where everything could be measured to the precision of 0.00001 (so to speak) and then corrected.
This is what Mohsin Hamid says in his interview:
There are more than a billion variations of lived belief among people who define themselves as Muslim one for each human being, just as there are among those who describe themselves as Christian, or Buddhist, or Hindu. Islamophobia represents a refusal to acknowledge these variations, to acknowledge individual humanities, a desire to paint members of a perceived group with the same brush. In that sense, it is indeed like racism. It simultaneously credits Muslims with too much and too little agency: too much agency in choosing their religion, and too little in choosing what to make of it.
And the point is let us start respecting these 1 billion variations of Islam (or any other religion) by others. And is there any other choice? May be we can move towards a more peaceful world.