ASEAN rightfully excluded Burma since many of the ethnic nationalities, especially in rural areas were mistreated. Much has been written about human rights violations and the abuse of the "common people" of Burma. Many of Burma's people are very poor and unemployed, and have no access to health care or education. ASEAN's inclusion of Burma was justified as long as its members verified that the worst abuses were corrected and Burma was encouraged to create a government responsible to and for its citizens.
No, it was not wrong for ASEAN to include Burma, because Burma wanted to work towards the goals of ASEAN. The goal of ASEAN, economic progress in the region and the airing of grievances without violence, it extremely admirable and overdue. It was appropriate to include Burma, because Burma wanted to work towards these goals.