Calling someone stinky is a personal & childish attack. It doesn't matter how you attach it to some other label.

What Kelley would have said if he were acting like an adult & offering professional criticism was that Jarred was a bad manager. Ineffective, even. That is what an adult would have said there.

an attack is not personal because it encompasses the whole person, but because it targets an aspect of that person. for an attack to be not personal it would have to target a category of people.

"software developers are stinky managers" is not a personal attack. neither is "managers are stinky", but "you/he/she/etc are something" is personal. it may not be an attack though if it is still part of a generalization: "you are a stinky manager because all software developers are stinky managers". but the article is not making that generalization, and therefore it's not just personal but also an attack.

Some people even like stinky!