Anonymous K joined in and replied with this 13 years ago, 1 day later, 2 days after the original post[^][v]#439,517
The authors almost certainly withheld studies that contradicted their hypothesis. The probability that seven studies with such small effect sizes would all reject the null hypothesis is only .02 (the standard threshold for publication bias is .1). It's also suspicious that the authors failed to cite the wealth of evidence that antisocial behaviour correlates negatively with socioeconomic status.
And considering that the studies were of Bay Area residents, Berkeley students and Internet-selected samples, most of the "lower class" individuals were probably not actually poor.