Certification and ability are different things. Contrary to popular belief, certification does not magically endow somebody with abilities, it only (slightly) raises the chances that person possesses necessary abilities. However there are a lot of people perfectly capable of teaching without certificates, and, unfortunately, plenty of people with certificates totally incapable of doing so.
Looks like the author of the article was either incapable or unwilling or unprepared to perform one of the basic teaching functions - ensuring that jerks do not disrupt the process for the rest of the group. It may stem from inexperience - well, that's what experience is for. One doesn't need masters or certificates to learn such things though, it's perfectly available to any common person.
"It may stem from inexperience - well, that's what experience is for"
Can't speak for US, but in UK a large part of PGCE courses is devoted to reflecting and acting on experience gained in a supervised teaching placement.
Sometimes you need to dig a bit deeper to process the experience, my favourite out of date theory is Schon's single and double loop learning.
For coders: single loop learning is when you change the way you name variables or re-write your code to make the logic clearer. Double loop learning is the stuff Michael Lopp writes about.
Looks like the author of the article was either incapable or unwilling or unprepared to perform one of the basic teaching functions - ensuring that jerks do not disrupt the process for the rest of the group. It may stem from inexperience - well, that's what experience is for. One doesn't need masters or certificates to learn such things though, it's perfectly available to any common person.