Sure it is.
The first arbitrary selection is which cultures can be appropriated and which not. No one complains when German culture is appropriated (Oktoberfest, Lederhosen, etc.). The general response is that it is ok to appropriate "white" cultures because they are "in power" or something like that. But for example the Greek were not "in power" for a long time, but are still fair game.
All of those mentioned are considered a part of the dominant European/Western culture, to which most of the people in the USA or Europe can lay some kind of claim to. There are literally hundreds of millions of Caucasians who could- but do not- complain about the use and depiction of their culture.
The second arbitrary selection is which culture "owns" what. Are dreadlocks part of "black culture" and no whites are allowed to have them as it was claimed?
Dreadlocks, while not unique to any one culture, are strongly linked to the religious beliefs of a particular subset of blacks. It is understandable that they complain about outsiders adopting the style. And, F.Y.I., some are not only displeased with the Caucasians who so, but anyone.
What about Vikings (ignoring for now that as white people no one cares if they are appropriated), who owns them? The Swedes? Norwegians? Danish? British? French? Ukrainian?
They are free to complain. No one is stopping them.
And, for the record, some do. Especially some of the neopagans I’ve met.
How many Irish Americans go nuts on St. Patrick’s Day without having ever left the USA? How many Italian Americans strongly embrace their roots without having visited Italy?Can an african american safely use things from an central african culture even though he never visited it just because of his skin color? What about cultures that have been gone for centuries?
Considering that many of us have absolutely no way of determining which African cultures we can genuinely claim as part of our ancestry because that knowledge was forcefully and deliberately eradicated whenever possible, you might want to reconsider your articulation of a double standard.
There are Africans who are just as prickly about the use of kente or batik patterns as there are Scots who bristle at non traditional plaids.
Personally, because I know my non-African heritage far better than I can ever know my African roots, I minimize my use of symbology from that continent. So I have an eye of Horus pendant, an ankh or two, but that’s it.