Thats just the point, these services are already outlawed. There are numerous laws that regulate the sale of drugs, weapons etc., which makes these onion-services already illegal. The wording of this proposal is made deliberately weak so that even Exit nodes will be covered, if it gets through the Bundestag.
Alas a small word on the legislative procedure. This is "only" a draft of a proposal of the Bundesrat (what in most states is called the Senate). The 'Bundesrat' has no legislative authority, so in essence this is a paper that 'calls the Bundestag (House of representatives)' to initiate a legislative procedure -- on itself it is pretty meaningless but has the chance to become a problem.