You see similar behavioral trends, sure, but the fact Karl hasn't always like this makes me think ODD is a poor explanation. Generally it crops up during childhood/adolescence, and adult diagnoses are very rare.
You say the fact that Karl hasn't always acted like this... When was he not? Damn near everything he's been doing for the past decade online fits this.
But, his decline into cowdom wouldn't have happened if he was unable to build relationships, or function normally to begin with.
Hence why I said "mild". Clearly he can function for a bit, but has some breaking point, and no matter the situation just has to shit himself to find an issue where there is none or take the biggest offense to the most minor of shit just so he could be some non conformist contrarian.
Joining TST?
Getting booted from TST?
Arfcom, in spite of his business arrangements?
His old nazi larp?
His double standards for purity tests?
Getting immediately asked to fuck off by the cowboy shooting community because he thought it was a good idea to immediately tell everyone on the forums that they sucked and how he'd change everything for the better?
Not being able to keep his mouth shut and losing business arrangement after business arrangement?
The cringeposting about totally not wanting to go to SHOT show when secretly wanting to go to SHOT show but he didn't get an invite?
For years always finding someone in his youtube comments to argue with?
Being excessively angry over minor shit for years at a time?
Making shit up to be angry about like the AI thing that no one really complained about in his revolver video a couple weeks ago?
Damn near everything he's done that's observable fits that ODD shit. Most lolcows aren't this consistent without actually being developmentally disabled and having a sub 80 IQ, and while I joke about Karl being retarded he's not actually retarded in that way.
ODD is brought up in other lolcow threads from time to time as many of them exhibit similar behavior (Patrick Tomlinson for example), but for an adult the diagnosis would be something different like NPD or BPD whatever. Karl was momma's special boy growing up (he's mentioned not knowing his father or his father walking out on them early on or something like that) and he was likely spoiled which led to the dingbat we know and love today.
This is true, but it's not impossible to have it as an adult, simply never getting over it as a child. Fatrick is definitely a terminally online retard, but clearly he's able to get something done in life normally outside of posting on social media. That doesn't seem to be the case with Karl.