It reads as someone smug just saying, “No, you idiot.” And they literally use “WTF,” as if it’s some statement of authority.
Further, that’s not even the right application of “don’t roll your own crypto,” reducing the credibility of the article.
“Don’t roll your own crypto” comes from people suggesting that you don’t implement your own copy of, say Diffie–Hellman key exchange, not making some calls to a RNG, which is ridiculously far more trivial.
Why always use X? Why never use Y? If you can’t articulate it, you’re not teaching anything.
And this guy supposedly teaches, too. What a shame.
Tell me: if you read this article and took away not to ever use floats in cryptography, can you tell me why? No? Interesting.