Thanks for the comment. I don't feel as though self-taught programmers have a bad name. I feel like they can lack some skills because the importance of them aren't lauded in their social circles. It wasn't until 5 years into my professional career that I was fortunate enough to work with someone with a computer science background, so the topics of Big-O never even came up.
I think computer science has a bad wrap for being useless brain-teasers used only in interviews (within a subset of the target demographic of this article). Through the bits I've managed to pick up, I feel like they contribute to a better understanding of programming on a broader spectrum.
While you may not see a body of knowledge that many people expect you to know (that you don't know) as scary, I can assure you that many people do. There are many similar topics that induce some amount of fear in me still: issues around multi-threading and race conditions, cryptography, deep understanding of networking stacks, and compilers to name a few.
I'd also like to point out some of the phrasing you've chosen. 'the idea that Big O is "scary" is just absurd' -> 'If you can't reason about algorithms, you may not be a very good programmer'. This is the source of fear among self-taught programmers (and the source of my own fear in the above examples). We all want to be good at what we do, so let's try to lift each other up! :)