Should...To?

Quote:

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Alluding to troubled spots such as Afghanistan, Gaza and Nigeria, Saxon Protestant Bishop Jochen Bohl asserted that people should not to put up with violence. The world has become "accustomed to violence" he said.

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It's a paragraph from an article, published on the German Wave web-site. I wonder, why did they write TO after SHOULD in the underlined part?

That's a mistake. It can be either "that people should not put up with violence" or "that people should not have to put up with violence".