FWIW, here are my 2 cents!
As a former cast member, I must say, most work
very hard at their job and do their best to maintain the magic. However, like at your work, there are probably some rotten eggs or some folks who are having a bad day. Who knows, maybe a guest was just rude to them or something bad is going on in their personal lives.
As much as I would like to say they should leave their issues off stage, its simply not realistic to think all cast members will be 100% perfect 100% of the time.
And, this may be a whole 'nother can of worms, but I think the economy and the price of admission has made the general guest more demanding as they try to get the value of the cost of admission making the cast members' jobs harder than they were. Maybe its because of that or becasue good people go on to bigger things, but I think the bar is lower for cast members in general in the last few years. There are still many superb and great cast members, but the average is of a slightly lower caliber in general.
So to answer your question OP. Yes, I think what you experienced were in general isolated incidents and that as you pointed out most are loyal to their home park. I think, psychologically speaking, its often referred to as an "us them phenomena." It's kinda the same thing as when you can bad mouth your brother but if the guy next to you does it, you are liable to punch them in the face! So I think us So Cal natives go to WDW thinking, "Oh yeah, WDW just try to top my DL" and visa versa. I hope your next WDW trip is a magical one!