ASEAN protects regional interests as the trading coalition helps create development goals for member nations. It doesn't jeopardize the culture of member nations as there are rarely any militaristic benefits to be gained by the organization. Instead, the coalition promotes free trade among members and tries to get better trading rights with other countries outside the scope of ASEAN.
No, ASEAN does not jeopardize the cultures of its member states, because one of the explicit purposes of ASEAN is to promotes the culture of its member nations. The cultures involved are very historically ingrained, and ASEAN does not affect most citizens on a local, pervasive scale, so it is unlikely that ASEAN is a threat to these cultures.