I have this theory: that anyone who claims "All theists are insane" have unrealistic ideas of what it means to be theists.
It is not necessary that you be insane to have unrealistic ideas, because there are very rational reasons to lie, and it has been shown that if you believe a lie, it is easier to convince others of it's truth.
There are also other rational reasons for believing things that are wrong, that don't imply deception: for example, faith is both a means an end, for many theists.
So please, if you believe theists to be insane, say so, but include two things
1: the definitions you are using for insane and theist
and
2: evidence that the two are, have been, or ever will be, the same