This thread just proves how many pilots are egotistical control freaks, trying to enforce their narrow view of life on others.
Fact is, as long as another captain stays within SOP and company rules, it has stuff all to do with you whether he speaks to pax from the cockpit or cabin, makes tea for the cabin crew or greets pax on their way out.
It is his flight to conduct as he wishes.
I can only assume that most of the critics are FO's. They do have the advantage of a mind uncluttered by command experience.....