Well you might be surprised to learn that even other Arabs describe them that way. I lived in Egypt for a while (in fact I'm on a visit now) and unfortunately most Egyptians feel the same way towards Khaleejis as your friends do. (Khaleeji=native of the Gulf region)
Needless to say I have met a number of very nice and decent Saudis and Kuwaitis. The thing is most of them go to other poorer Arab countries such as Jordan, Syria, Lebanon, and Egypt for vacation. Being considerably more well-off, the natives of these countries subliminally think of them as condescending and arrogant even if they aren't. Of course, there are some very nasty ones. Not to mention the sex tourists who go to these countries just for sex and alcohol.
I don't think it's subliminal, and
despite the presence of nice, kind khaleejis, this attitude is a reaction to very real behaviors on the part of summer vacationers. There is a difference in attitudes towards khaleejis who come to live in these countries for the weather, the better schools, or whatever and the ones who descend on the other Arab countries in the summer. I did not hear people speak bad words about the expatriates who come there for university or who want to raise their children there. But people cannot complain enough about summer khaleejis.
I think it stems from resentment towards the summer tourists, because when the khaleejis come to town, the government, the security forces, the local economy all orients itself towards pleasing and serving the khaleejis, sometimes at the expense of local people - citizens. The streets in some Arab cities are choked with more traffic and headaches during khaleeji time than the rest of the year - and anyone who has driven an Arab street knows how bad it is already. Their arrival drives up housing costs and you sign a year's contract for a lease, so if you are forced to find housing for yourself when the khaleejis are in town, you will have to pay that super high price that set the market in July, even if the same house or flat would go for much cheaper the other 9 months of the year.
The men would come to town - not the Emiratis, but Kuwaitis and esp Saudis - and they harass women in the street, even women in niqaab. I cannot tell you how many times I've been harassed by Saudi men young and old who have never seen a female other than their mother or maid, and certainly not one in full hijab going about her daily business alone, in public. When the summer khaleejis are in town, you have to turn your Bluetooth off on your phone, because they will bombard your phone with love notes, pornographic images and propositions. My feelings towards them after this were not subliminal, let me tell you. And while perhaps based on exaggerated fears, we all know that if a Saudi family with men present was renting in your building or your neighborhood, you had to be especially vigilant with the boys (of course most families already keep a tighter reign on the girls). Mind you, pederasty is already widespread even in the poorer Arab countries, but when the khaleejis came to town for the summer, we were actually afraid for our boys. For whatever reason, the threat of abuse was more immediate to people from the khaleejis, even though if the boy is going to be abused, it's more likely another local who will do it to him.
Topic: Why are so many Gulf Arabs into Gay sex