Where has anyone said that? I assume you can post a direct link to where someone has explicitly said "All Arabs", otherwise you will make yourself look very very racist and a liar.
It is an established fact that Prince Charles accepted a charitable donation in cash from the former Prime Minister of Qatar, yes. Everything else, including the spin all of you are putting on the donor/the source of the money/the legality of it is all supposition.
No. It's on the record fact that Charles broke all advice and protocol to meet with the Qatar Dictator alone in a hotel room, refused to permit any kind of advisor to be present, and accepted suitcases full of cash.
The Tory government sell arms to oppressive dictatorships that execute anyone who criticises them and engage in torture, human rights abuse and genocide, knowing those weapons will be used in genocide and attacks on civilians. The excuse "but the Tories work with war criminals and terrorists too!" is pretty shocking.
But what would you expect from people who think wearing nail varnish is evil but rape, child abuse and human rights violations are just fine and dandy.