Saying "Zcash is not private by default" is deceptive in at least two ways. 1) "No default" is not the same as "transparent by default". By capitalizing on negation scope ambiguity "not private by default" suggests the latter when the former is true of the protocol. 2) As the protocol allows either, it's up to a UI to enforce a default if they want to. The major wallet apps have long made shielded the default. When people deceive you with carefully crafted deceptive phrasing, it's wise to take note and adapt your trust.