Career
In April 2009, Sun was heavily criticized because of statements he made about petitioners in China and the xinfang petition system. In an interview with China Newsweek magazine, Sun "thinks at least 99% of China"s petitioners (訪民) are mentally ill", and he supports "the forced hospitalizations of mentally ill petitioners". Sun has stated:
.. Hospitalization of (a mentally ill person) is the greatest safeguard.
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He is a danger to society and also a danger to himself. We must bring such a person in for treatment and speed up his mental recovery. In this way his human rights will be protected.
In response, many Beijing petitioners went to protest against professor Sun Dongdong at the entrance of Peking University, shouting slogans "Put Sun Dongdong into mental hospital".
Sun later issued an apology for his comments, stating he expresses regret for his statements.