Deborah, I have not tried to check the sign-up materials to verify what they say about FamilySearch, however I expect that they specify that records can be found at FamilySearch and these are valid sources. I would hope that they make a distinction between records and (mostly) unsourced family trees, which can also be found at familysearch.
Primary and secondary sources are a whole different matter, though. A primary source is one that is accepted as proof of a fact, while a secondary source is accepted as evidence, but less than absolute proof, of a fact. For example, a death record is a primary source for the date and place of a person's death. Death records often have additional information, such as date of birth, but are considered only secondary sources of this information. Unofficial records, such as a family tree compiled based on family stories, are neither primary nor secondary sources, although they can be good hints that help direct you toward finding actual sources.
In addition to records, familysearch has family trees and we need to make a clear distinction about this. The records are excellent sources but the family trees are not, although they sometimes do have records attached, which makes it easier for you to find the records, but you should be citing the records (not the family trees) as your sources.
As to your initial question, you are absolutely correct that many WikiTree profiles unfortunately have only a family tree ... or worse, a statement like "grandma said so" or even nothing ... as their source. These are not acceptable as sources for pre-1700 profiles, although WikiTree relaxes the source requirements for later profiles, but we are strongly encouraged to make the effort to find better sources. As Chase pointed out so well, there are more profiles with bad or no sources being added every day than there are members who are willing to put in the time and effort to get the ones already here correctly sourced. We just do the best we can ... and keep hoping that more people who care (like you do) join and help the rest of us who try to fix as much as we can.