text: "As a sign of diversity, I would like to see those of various religious faiths (and the faithless) be intermingled in their burials."
  
  That might be what YOU would like. And perhaps in a perfect world Catholics (say) wouldn't mind being buried beside a Satan worshiper. However, in the world we inhabit people place considerable importance in their religious beliefs, the afterlife and their final resting places. And if those matter to them, why should they be prevented from being buried in the manner of their choosing? 
  
  I can think of one reason: if the cemetery is publicly owned. In that case everyone who's buried there must accept non-discriminatory rules. A Catholic may indeed be buried next to a Satan worshiper. However if the cemetery is owned privately, as are most church burial grounds, then different rules may apply.
  
  If you want to be egalitarian in your choice of a grave, get buried in a public cemetery. But it's reasonable for people to have other options as well.