The emphasis on "disaster" is a bit misleading. The guy was talking about being prepared for all eventualities, but both volcanoes in question have repeatedly had small, non-disastrous eruptions.
I think a lot of recent articles quoting Indonesians haven't been accurately capturing the gist of what they're trying to say.
Well, if the eruptions wouldn't cause a 'disaster', then why bother evacuating?
Maybe the headline should have read 'potential disaster'.
I understood the content and context just fine.