The way I see it, psyche is an extremely complex mechanism, and in order for a human being to function properly through life, it has to be balanced. It is a fact that we (the humanity) do not know everything, and there are things that we can’t currently explain, i.e. there are blank spots in our knowledge. The mere existence of those blank spots throw a lot of people off their balance, which is why they experience deeply rooted discomfort on that account, and try and fill them in as a means of compensation. Even though what they fill them with are nothing but fantasies with no substantiation in reality, it brings them psychological comfort that is so necessary for a relatively healthy mental life. It is true that this comfort is based on nothing but illusion of knowledge, but that doesn’t make it any less real.
I myself do not require religion to go through life without killing myself (or, better say, delusion of religion doesn’t really work on me), but I can understand why others do, and I don’t think that I (or anybody else, for that matter) have any right to deny them that.
But when they start thinking that they know better what’s good for me, there appears a problem. Under no circumstances such attitude/behaviour can be tolerated.