Namespaces have underscores in their proper names. In DPL3 (versions older than 4.0.0), when excluding a namespace that contains a space (such as Help talk), you must replace the space with an underscore — e.g. Help_talk. Using a space instead causes different results and the exclusion will not behave as expected.
This is fixed in DPL4 4.0.0 and later, where spaces in namespace names are handled correctly for exclusions.