Maybe it's because the "Collaboration Pool" members realize it's a losing battle from the get-go!
In theory, collaboration is good - an exchange of information. However, I am finding the opposite is true in several other genealogical groups I belong to. It appears that many "collaborators" are not exchanging information at all. They are simply taking information I give them and do not give back credible information in return.
Example #1: y-DNA shows that my family has gone under the surnames Calvert, Colvard, Colbert, etc. There are literally hundreds of family trees that indicate my family is related to 1st Lord Baltimore George Calvert of Maryland. However, y-DNA proves otherwise as well as FTDNA Family Finders. When I inform these "collaborators" that my family is not a member of Lord Baltimore's tree they refuse to accept my evidence and continue to keep my family as a member of Lord Baltimore.
In essence, they prefer to believe in the "lie" than in the "truth."
A prime example is families related to the Colbert's of Pittsylvania Co, VA. FTDNA Family Finders shows that I am a distant cousin to eleven families in Pittsylvania Co. Yet everyone of those people I have contacted swear they are related to Lord Baltimore. (None of these families are direct members of the CALVERT or COLBERT family, but they are related by marriage to the COLBERT family that moved there in the 1790's). Nothing will sway them. Not even the land deeds showing that families I am related to in Accomack Co, VA moved to Pittsylvania Co at the same time that the Colbert family did -- Stockley, Donelson, Purnil/Pernell, and Bibby (Bybee). [John Donelson married Rachel Stockley in Accomack Co and moved to Pittsylvania with other family members. Descendant of John and Rachel Stockley Donelson was Rachel Donelson who married President Andrew Jackson].
Example #2: While I am not related to Lord Baltimore, I do have the same DNA as the Chickasaw Colbert's and literally hundreds of "Colbert's" say they are also related to this family, even though they have never taken a y-DNA test and refuse to, and they have no Primary Source Material to prove they are related to the Chickasaw Colbert's.
It reminds me of the old saying: "You can take a horse to water, but you can't make 'em drink it."