Attribution just means crediting an author
The Creative Commons consortium refers to parametric licenses that require attribution as "by-", so the "by-sa" license requires both attribution and share-alike terms. The GFDL license requires the five most prominent authors to be credited so it too has an attribution requirement.
Trolls seem to think that any attribution interferes with the free circulation of fiction, and that usurpers and Wikimedia corruption prevent sharealike use that would make all large public wikis equal. For instance, they promote interwiki link standards that do not put any one source at the centre of the universe, and strongly oppose GodKings on all wikis. This is just one more issue in wiki governance.