Earlier quoted context omitted.
There's a difficult rabbithole here - eventually you have to draw a line and decide to trust someone . Otherwise it's just layer after layer of paranoia until you implode in a puff of Philip Dick :)
Of course; my point is (and I assume that's also the point of other people who assert similar stances on the topic) that the average programmer or software engineer should leave these things to recognized cryptographers. This also highlights a peculiarity with cryptography, in that it is very hard to understand for laymen (assuming laymen are ppl with some CS or math education), so most arguments in discussions of la…
If "crypto is for cryptographers" is your stance I think you're doing yourself a disservice. Understanding crypto, as in learning the foundations of it, is important for everyone. Having a good grasp of cryptography helps with making decisions in your code base w.r.t to how you use cryptography primitives and tends to help you in identifying places where it's gone wrong.
I agree that it's easy to get these things wrong but I don't think that's a very good reason not to try to write or read up on the subject. And yes, it's possible that what you get taught might have holes too. But it's easier to fix these holes, for example by having discussions around the topic with others and validating what you're being taught, than acquiring the knowledge to begin with.
Now the author in question (lvh) is also known for their contributions to caesium (Clojure implementation of libsodium/NaCl) and Python Cryptographic Authority's cryptography library. They've got some solid chops in the area but make of it what you will.
That said, rolling your own crypto should be left to cryptographers with extensive peer reviewing and so on.