There could be several reasons:
- He was, but things change with time
- He just didn't express it
- The classmates were given the ability to protect themselves, but they fell from their own doing (overconfidence, misplaced trust, etc)
- They willingly accepted at first, maybe some felt pity for the world's plight, others were chuuni, and the rest just followed the majority opinion
- The goddess counts more as a force of nature than anything else, it's like getting angry at a storm
Without more context clues we can't really know, but there could be plenty of legitimate reasons for that.
The assumption that because we're only seeing a quick breakdown, that's all there is to the story is inherently flawed.