Perhaps you should think about it a little more carefully H.
Israeli Jews are not black. Israeli people who come to Australia are not dark skinned...you can't tell them from Aussies until you hear their accent.
Some of the Arab nations are olive skinned but they are not black either. If the nation of Israel were not very dark skinned people and they were forbidden to marry outside their race and religion, then black skinned individuals would have been a rarity among them, don't you think?
Since angels appeared to God's servants who were not dark skinned, why would they appear as people of the nations, with whom the Jews had no dealings? Common sense isn't it? Why are you looking for racism?
It was with the spread of Christianity that dark skinned peoples were given the opportunity to respond to the good news along with many other fair skinned people of the world.
Jehovah's Witnesses come from all nationalities, including indigenous peoples where white conquerors invaded their land many centuries ago. They form one brotherhood from all nationalities and backgrounds who all love one another without prejudice.
Just so you know.....the pictures in the WT publications are designed to reflect the ethnic backgrounds of the people in all nations. In Asian nations, the people depicted in the magazines are Asian, in African countries, they are African people. We do not favor one race over another but try to speak to all people in their own language and with familiar looking people in their publications.