No, Arabic culture does not have a larger proportion of left-handed writers. The proportion of Arabs who write with their left hand is unknown. However, the proportion of the world's population that writes with their right hand (about 90%) is most likely also true in Arabic culture. Therefore, if left-handedness was common among Arabs, we would expect to find some evidence of this in the literature. In fact, the only study on this topic that I could find used autopsy data from Iraq and reported that there were no significant differences between the left-handed and right-handed populations in terms of frequency of death due to natural causes or violence. This means that left-handedness is unlikely to be an important factor when it comes to writing in Arabic. There are some theories about why more right-handers exist on average but they all involve biological factors. For example, some researchers believe that left-handed people are more likely to suffer from illnesses such as cancer because the body is forced to use its immune system more often. There may also be environmental factors involved - for example, there are reports of war zones having higher proportions of left-handed people because those people are less likely to be recruited by terrorist groups. However, none of these theories can explain all the cases where left-handed people do appear in large numbers after a major trauma such as a war or earthquake.