It is not a cult like following, it is because CBCS has blown their credibility with consistently looser grading at the wrong time. When Steve jumped ship there were plenty of collectors and dealers that followed, only to return when the loose grading killed the value for the books. Personally, I find that CBCS allows too many of my pet peeve flaws go in higher grade books so I pass on them even at an attractive discount.
Every company has its tighter and looser grading periods. Heck, there was a time when PGX had tighter grading than CGC - I know based on submissions I made there during another extra long TAT period at CGC. I thought they looked better, and this was confirmed when I resubbed them to CGC and received higher grades on every book without pressing and cleaning (I did not know what that was way back then ). Over time, CGC has been the most consistent of the grading companies and as a result it is the one that buyers trust.