Fact 1: In most versions of Dungeons & Dragons, when infected – as opposed to natural-born – lycanthropes transform under the full moon, they assume the default alignment of their type during the ensuing mindless rampage.

Fact 2: In most versions of Dungeons & Dragons, the default alignment of werebears is Lawful Good.

Conclusion: When an infected werebear transforms under the full moon, they go on a mindless Lawful Good rampage.