Chinese (and to some extent Indian) groups of tourists tend to behave maladjusted compared to other tourists. You can observe it all around Europe too.

In the Netherlands a recent phenomenon is Chinese tourists wading through the famous tulip fields this time of year to get the perfect photographic memento. Tourists from other cultures mostly respect the societal boundaries that prevent you from just barging in and damaging a farmer's crop, but the Chinese tourist just doesn't see those boundaries (whether it is an explicit sign or just the common sense that these flower fields are not part of a theme park but an actual agricultural enterprise).

At any rate, to them everywhere they get herded to in touring buses is a theme park; historic city centres, tulip fields, authentic windmills, etc. They just don't see that people live there, or make a living, or that some old building may be a natural treasure, not a theme park replica you can safely climb on.

It might be a mindset thing. Chinese tourists seem to expect that people around them (tour guides, local staff) tell or show them explicitly what to do and where to go. Without guidance, they end up stepping into cordoned areas, passing no entry signs, and wandering onto private property.

The solution to the Chinese barging through your flowers seems to have been found in changing the communication strategy. Instead of signs forbidding entry (which get ignored, even when written in Chinese) they now put up banners asking visitors to respect the flowers (in Chinese) and not trample them. It seems to help a bit.

The article lists "...according to local police, about 95 percent of petty crimes on Jeju are committed by Chinese", but that is less than useful without statistics on tourist demographics. It would be interesting to see a more comprehensive study - I wouldn't be surprised if there's a lot of confirmation bias (for Americans as well) due to their large portion of the tourist population.

I think the answer is No, Chinese are not worse behaved overall than other tourists that I have seen.

Their voices are a little louder sometimes, but that's the worst I can say. Individuals may behave badly, but then the same is true of individuals from any other nation.

I've had cause to ask two people to modify their behaviour at Tokyo landmarks recently. One was a juvenile Italian swinging from a torii gate, the other I believe was Nepali and he was just standing on the wrong side of a picket fence to get a better photo of himself.

I've seen a lot of Chinese, but they are no worse or better behaved than others in my experience.

At the Louvre in Paris there is a sign asking tourists not to poop in the street. The sign is only in Mandarin.

Certainly not worse than terrorists/bombings/etc. from cultures which I will not name.