Please note I am not fingering Rob or Dan at all in any way. Given how crazy this guy must have been, it's possible Mr. Paddock had MANY stressors going on where he came precariously close to committing his heinous act, yet Dan banning Rob (for his own good, albeit unwitting reasons) might have been a "straw that broke the camel's back" sort of catalyst which sent the shooter over the mental precipice.
All I am trying to point out is the timing of all the events is highly intriguing, and the shooter's past career and lifestyle preferences could have given him a high degree of personal relatability to Rob. The shooter may very well have been a quiet fan of Rob's non-VP lifestyle, and Rob was possibly the shooter's means of comic relief which may have been snuffed out by the banning.
The shooter was apparently highly successful in real estate and Rob often talked about that matter a fair bit here, as well.
I could see where Mr. Paddock may have quietly viewed himself as Rob's superior, and amused by Rob's antics because of the lifestyle similarities. Rob and Mr. Paddock seem to be opposites there: Rob did all the talking/writing, and Paddock did all the reading/listening.
This is ALL conjecture on my part, yet very interesting conjecture, though. Who knows?