Someone on FB posted another similar article
They took a high saturated fat diet and also made it high glycemic. Then they noted that the incidence of something (can't remember because it was a forgettable study) that caused Alzheimer's. Then they reduced the saturated fat (as well as the high glycemic index foods - per their own admission) and lo and behold, it went down.
WTH happened to changing one thing to see what happens?
High saturated fat + high glycemic = Alzheimer's
Low saturated fat + low glycemic = no Alzheimer's
Therefore saturated fat must cause Alzheimer's.