To be clear, I certainly do think racism and cultural appropriation are topics to be taken seriously. From a business standpoint, it's not a good idea to produce content which may be offensive to a portion of your customers. Though, it's not always easy to determine where the line been appropriation and inspiration is set. (And I would posit that some of that is because we live in a contemporary culture which has created something of a fear concerning even discussing those issues openly, but that's likely better suited for something other than a RPG forum.)
I'm not sure if this is better or worse, but sometimes I will start with a piece of a historical Earth culture (because I'm not familiar with cultures from the histories of other planets,) but then consider how those concepts may change or be altered to better fit biological differences, differences produced by climate, and the existence of fantasy monsters. (Though, even here, a line must be drawn somewhere. Sometimes, going too far down the rabbit hole of making something believable detracts from making something playable -even as someone who likes to have touches of "realism" in fantasy.)
For example, in one of my settings, dwarves^ are based upon Asian culture (rather than the typical Viking & Scottish or Irish mix). More specifically, I based some of their cultural ideals upon the Warring States period of Japan and Three Kingdoms Era China. Dwarves are often described as leaning toward lawful (in terms of alignment) and having some manner of clan structure. As such, the idea of Dwarven Daimyos and clans vying for control through an elaborate mix of polite diplomacy and warfare made sense to me.
(^FWIW: I have two types of dwarves in this particular world. One is a mix of Warring States Japan, Three Kingdoms China, and D&D Dwarves; the other is loosely based on a blend of Grecco-Rome sword & sandal fantasy, Dragon Age Dwarves, and Catholic Saints.)
Though, that lead to questions of how things changed when I blended the two ideas. The mental picture of a dwarf samurai^ was kinda cool, but dwarves are traditionally known for using axes and hammers. Sure, I could change that as well, but I was already doing a radical departure from what players usually expect, so I wanted to keep some familiarity*, so as not to create something completely alien from what players know.
^I believe 3rd Edition's Complete Warrior featured a dwarf as the iconic samurai.
*Which may be a comment relevant to the topic of this thread. A lot of fantasy ideas and tropes are commonly known, and it tends to be easy for someone to sit down at a table and join in without putting a whole lot of thought into understanding the narrative of the world.
So, that lead to thinking what a (for lack of better words) katana-version of an axe might look like because, just as players may have preconceived notions of what a dwarf is like, players also have certain images of what being a samurai includes. At one point, I had a mental image of something similar to a Klingon Bat'leth, but used the opposite way (which is to say that the convex curve would be the striking surface, and the handles would be on the opposite of where they are for the Klingon weapon.
It is around that time that I also entered into a discussion with a friend about whether or not it made sense for dwarves, a group of people known for living underground and in close-quarters, to rely on weapons best suited to wide swinging arcs. So, this lead to considering some manner of hybrid axe/spear. I am still in the process of mentally sketching that out and reconciling that with the fantasy image of a samurai.
The point is that I started with one piece or one idea, but I modified it. I'm not sure if that is appropriation. I do not feel I am presenting the culture in a negative light (nor would my intent be to do so). But, perhaps someone would be offended by having a portion of my campaign world focused on samurai and ninja tropes. I cannot for sure say how others may view that.
In the event it is viewed as offensive, I feel that I would also need to re-evaluate orcs, hobgoblins, and many of the other traditionally evil humanoids because they tend to be caricatures drawn from Euro-centrically negative views of non-European cultures. Orcs often tend to be a blend of what were seen as negative traits among tribal cultures and (occasionally) the "one drop rule" pertaining to a human obviously not being of pure blood if mixed. This comes full circle back to determining where the line between appropriation and inspiration is drawn, and -similarly- where the line between real-world social issues and setting the stage for a fantasy game is drawn.
