SMARTCOOKIE,
People may honestly beleive that g-d exsists but not that he gave the torah
or that he gave the torah but that most of its laws were written for those days and just the basic ideas in it still apply (c’v),
or even that hashem is happy with them for who they are without being shomer shabbos and keeping mitzvos as long as they are prodoctive members of society
or that he just gave the eseres hadibros and the rest was written by moshe rabbeinu
among a host of other things that you or me may find wierd,illogical or even impossable to beleive.
Remember the vast majority of humanity finds the vast majority of the things that we beleive to be wierd and alot of them wonder how we can beleive them.