I agree the oxygen mask remark was weird. Anyone who has read anything about the monarchy knows that its popularity rises and falls. It wasn't unpopular before Meghan, maybe a bit boring, but not unpopular. I don't remember reading articles demanding racial diversity within the family which would be the only context that makes sense.
Is the writer American? I have found a tendency in Americans in general, and you can see it in Meghan, to expect the UK to have exactly the same racial issues and context as the US and it just doesn't. Yes we have problems with racism but they aren't the same problems because they arise from our history not theirs.
The other difference I find when discussing the Royal family with my American friends is the difficulty in explaining the way they intersect with culture and society and history. We want to see them in tiaras and carriages but on a day to day basis we expect middle class thrift (the Queen's tupperware, Charles' ancient suits) and a lack of pretension.
The whole thing is a bit weird and complicated and I think a lot of us didn't realise how complicated until Meghan married in, obviously without any preparation or warning from Harry, and then failed to grasp the details and expectations of what she had married into. And how could she, I know she refused the Aide and Sophie but I would bet good money that Harry was in her ear getting her to refuse.
In summary, she wasn't an oxygen mask, she was a victim of Harry's preference for feelings over facts and truth.