Human memory processes and recalls images much more capably and efficiently than written text. Microsoft was merely attempting to use this truth from educational psychology and memory studies.
News Flash #1: An attacker with the wherewithal don't need Recall. They have hundreds of options to surveille your use of a PC - Windows or Linux - from screenshots, to keylogging, to continuous monitoring, to usage history, to just about anything you can imagine.
News Flash #2: Nations and their governments do not need Recall either. They already got your number. It is trivial for them to find you (unless you live off-grid deep in the forest). It is trivial for them to piece together your daily life - including your digital life.
Now, if you are boffing your wife's or husband's best friend (or secretly living another life doing stuff that you feel compelled to hide from others because of negative consequences) and they're sending you sweet love messages and sexting, and you're logging into social media or email accounts to view that stuff, well then - you've got a much larger problem than trying to hide your porn addiction. Recall is gonna provide divorce evidence. You're gonna pay alimony for infidelity.