I reckon all bears, given the right circumstances, will kill you and eat you. But, the big Brown Bears of the northern hemisphere seem to be particularly ill-tempered.
The Journals of Lewis and Clark offer one of the most comical 180 degree turnarounds in history.
The party had been hearing stories from various Indian nations about the “white bears” all the way up the Missouri. Pretty much completely unknown to science. Lewis noted that the warriors only attacked in groups of up to ten or so, and often got killed. They saw these huge 12” tracks and got pretty excited.
But they still didn’t get it. Lewis figured that the Indians, armed with indifferent rifles, bows and arrows, were no match for Infantry with modern rifles and aimed fire. He wrote basically, it was all hype and exaggeration. Oops.
Then, they started getting attacked, and they couldn’t believe how hard it was to kill one. “I believe the curiosity among the men about these bears is pretty well satisfied. I do not like these gentlemen, I’d rather fight two Indians than one bear”