When is it legitimate to censor an entry?

In the "City of Lisbon" challenge ( open for voting ), the host has removed an entry showing the "Monument to the Discoveries" - a very famous and frequently photographed Lisbon landmark commemorating the death of Henry the Navigator and other Portuguese sailors who discovered and obviously later colonised South America.

The host has decided that the entry was a "political statement' and not allowed.

I have asked him, why in that case, he had allowed in his earlier challenge  "City of Beijing" the photos of the communist dictator responsible for the deaths, torture, starvation, labour camps etc of millions of Chinese people? These could be interpreted as statements glorifying a criminal political system. His response was that he had not received any protests.

When is is OK for a host ( from South America in this case ) to censor a challenge to suit his own political views/persuations?

I presume, he personally feels strongly about the European settlers in South America but is oblivious about the history of other parts of the world and therefore is unable to make a right judgement.

My view is that he should have allowed BOTH entries as the only criteria - i.e ANYTHING taken in Bejing, of Beijing or of Lisbon have been met. Both have depicted a historical reality - a fact of the past, whether someone likes it or not.

What do you think?