In this case, that happens to be preventing poor passwords. That is a concrete, real-world problem, requiring practical solutions, which these patents purport to provide (probably) novel, non-obvious variations of. For example, one of the less "decent" patents uses (what seem to be) bloom filters to track and test for poor passwords. This does not mean all uses of bloom filters are covered by it. The claims specifically cover the method of using bloom filters to test for bad passwords.
Really, it becomes clear what is covered when you simply read the claims.