Considering that many consider (i) politics as serious issues which impacts their reality and (ii) sports as on outlet of escape from the everyday world for most people, mixing politics with sports is bound to get people heated at times.
Thus, it is only a decent thing to do to exercise your freedom of speech in a respectable manner instead of intentionally disruptive manner. Take this case for example, they could have demonstrated peacefully outside instead of antagonising the players and spectators during the game, possibly jeopardising the game for those looking forward to it and also putting the host nation in a difficult and awkward situation.
At the end of the day, based on the reporting, not only did the Tibetans not achieve any significant result (they were asked to keep away the flag), it also created as well as left quite a negative impression towards the Tibetans rather then against the Chinese.
