And how does one define weak and weak-minded? Obviously we're talking about mental weakness; but can we narrow it down from there? How about "unable to think for themselves"? But what does this mean - unable to make any decisions other than the most basic that are necessary for life? Being uncreative? Being a conformist? Unwilling to think critically about issues? I'm guessing that it's some combination of those.
For a definition of religion, please see that node, or just read this shortened version: a set of beliefs based on faith, not empiracal evidence, about the supernatural. Is not the same as witchcraft, sorcery, or magic.
One obvious reason to think that religion is a crutch for the weak-minded is because religion answers questions that we mortals are unable to answer on our own: things like "what is the meaning of life?" and "what happens to us after we die?" Having these questions go unanswered causes varying degrees of anxiety in people. Trying to set aside other factors such as the fact that the religion you are taught in childhood will have a profound impact on your religious views later in life, presumably the people who cannot cope with this anxiety will be religious, and the people who can cope with it will be atheistic.
Now, let me ask you this: shall we consider all forms of anxiety to be equal? In other words, if someone has another cause of anxiety (any number of reasons: acrophobia, depression, bipolar disorder, the loss of a loved one), and they rely on prescription drugs to quell this anxiety, does that make them as weak-minded as people who are religious? Are their drugs a "crutch"?
I will let other noders elaborate upon this - I put it forth to make people consider just what exactly they're thinking.
On to the other definitions of weak-minded: the conformists, the people unwilling to think for themselves. It follows that people unwilling to think for themselves wish other people to do this thinking for them. Wham-O, that automatically eliminates religious people who are either not part of an organized religion; or who are part of an organized religion, but hold some beliefs that differ from the doctrine and/or dogma of said organized religion. Such people are obviously willing to think for themselves, at least in some cases.
Moving right along to the yahoos who could not even conceive of the idea of questioning religion: we all know these people. They are the smiley-faced "John 3:16" bliss-pests asking Have you found Jesus?, they are the people who hang out on college campuses with big signs that say repent or you're going to hell! Not necessarily Christian, but it is an example that most of us are farmiliar with.
So, do these particular induhviduals think that religion is such a good thing because it is easier for them to accept a pre-packedged set of morals and ethics than it is to debate on the question of life, the universe, and everything? Yes, it is entirely possible. Is "fitting in" more important to these people than free thought, and organized religion is just one more way to conform to their society? Yes, it is entirely possible.
Thus, a more accurate statement might be, "Organized Religion can be used as a moral, ethical, and/or social crutch by people for whom independent thought is difficult or undesirable." But so can political ideologies.