Lars is technical, he's just not proficient in a traditional way. He's incredibly creative and plays things oddly (compared to his contemporaries), which a lot of traditional drummers call "wrong". Never made sense to me why Jimi Hendrix was a genius but Lars gets ridiculed, they're very similar in that way. He didn't keep up his chops as he aged and now has trouble playing a lot of the things he wrote when he was younger. But his contributions to the songwriting and very unique style influenced a generation.

All that being said, I think this timing strangeness could absolutely have started because that's how Lars played it (intentional or not), and everyone adapted to him because it's cool.