I wouldn't go so far as to say it has a positive meaning because many people are over enthusiastic to the detriment of others when they become something-baka.Baka also has a positive meaning as well when you use "noun + baka".
Karate Baka means something like an ardent karate enthusiast
For example tsuri-baka\釣り or fishing crazy/enthusiast their enthusiasm often times comes at a price that their world revolves around nothing else BUT that which they are -baka- in.
I'm guessing it's worse than kuso and chikushou.
These two terms are generally used as exclaimations and not directed towards another person.
However any of them could be offensive in the tone and delivery of the user. Just like saying s**t or f**k can be used as exclaimations in English as well. Yet if directed towards another person with the intent of cursing someone out there meanings change dramatically.
btw, question here, why is profanity in English filtered out here but not words that are considered profanity and not usually used in common speech in Japanese not filtered out? Profanity is profanity right, or is everything selective. I have heard that to some English users the word f**k is not that profane and is used in common language as an exclaimation, just as kuso or baka in Japanese. Things that make you go hmmmm.....