Most photographers like to make pictures, but aren't really sure if it is OK to make pictures that please themselves.
As they begin to try to learn about photography, they encounter the folks who need to FOLLOW rules, and the folks who need to MAKE the rules.
These co-dependent photographers, pundits , experts, followers, disciples (while generally well meaning) spread havoc and confusion,
and infect the innocent photographers. Nothing new, although the Internet has made it possible for anxiety and distraction to spread with terrible efficiency.
Those that survive their infection with rules and dogma (like sharpness) generally are immune after their recovery, until they are exposed to another cult trolling for acolytes.
The 'great' photographers were seldom dogmatic, nor were the great teachers. The former, fully interested in making good pictures; the latter, fully interested in helping their students make the pictures the students want to make.
It IS good to know how to make sharp pictures, in the same way it is good to know how to brush your teeth and make a good cup of coffee. Technique IS important, but, as Baudelaire said, long ago, "Technique Is Impotent to Create ANYTHING." Keep your can of sharpness in your camera bag until you need it; you don't have to drink it.
There has never been a greater photographer, nor more profound influence on Photography than PH Emerson, who maintained that a picture be sharp enough, but too sharp. To the Victorian rule makers, this was a horrible, horrible thing. The idea that a photographer could decide for himself what constituted a good picture and how to make it, challenged their very existence.
Not much has changed in 110 years.