<p>Around the location of stigmatized facilities, people regard local residents as the concerned parties, who are more negatively affected by those facilities, and unquestioningly prioritize the rights of them compared with other parties. This phenomenon has been defined as the superior legitimization of concerned parties. However, when the concerned parties are prioritized unquestioningly, chain of rejections of the facilities by all dominions should undermine total social benefits, because many stigmatized facilities are in not-in-my-backyard (NIMBY) issues. Moral foundations inducing intuitive judgements are hypothesized to determine the unconscious prioritizing the concerned parties despite the irrational goals. The present study arranged two types of concerned parties around the high-level radioactive waste storage facility, which are residents in a dominion of the location site for the facility, and residents in other dominions of nuclear power plants in Who & Why Game on the Web (Web-WWG). The former will suffer from the location of the facility, besides the latter will be adversely affected negatively by the decision to not locate it. The superior legitimization of the former was reduced in the multi-polarization of concerned parties who conflict on their interests. Furthermore, effects of moral foundations on the former’s legitimacy were observed. We discussed intuitive processes which might background the superior legitimization of concerned parties.</p>