Looks like I'm late to the thread again. It was posted about 48 hours ago, and I see that there are already 27 pages of commentary...
I didn't read every comment, sorry. But just skimming the first few pages I see that someone already posted an image of burning books, and there have already been multiple insults, warning flags, and moderator comments. So we clearly haven't learned much from the other "racial issues in D&D" threads, and I don't think I missed very much by skipping over them.
But to answer the questions in the OP:
Should WotC remove the 1E "Oriental Adventures" rulebook from the DriveThruRPG.com marketplace? How about the 3E version? Other products that built on Oriental Adventures? What other titles?
Yes, I think they should. Even the title alone is problematic, to say nothing of the cover art, the caste system, and the whole book. It's the quickest, easiest, and least-costly way they can show their solidarity with a large portion of their gaming community. I would do this for all products in the "OA" line, for all game editions.
Another good option, if they didn't want to fully miss out on the revenue from book sales, would be to add a disclaimer page to the PDF, as well as the product description on the website. Something similar to what Loony Toons did, to address these same issues in their older media:
This is just the tip of the iceberg, however. There are some pretty problematic titles in the past that need to be addressed; one of the biggest offenders that came to mind is the "Drums on Fire Mountain" module. There are racial elements in "The Isle of Dread" that could have been done better, and could use an update. (And I say this as someone who loves that module...X1 is one of my all-time favorites, warts and all. With a little polish and a solid update, it could be even better.)
I think a lot of non-Asian people are talking out of turn here, giving their input on topics they don't fully understand, and things they can't relate to. Your inability (or unwillingness) to see the problems does not mean there are no problems to see.
If anyone has strong issues (for or against) on this subject, I recommend listening to the "Asian Reads" series of podcasts that explain the issues fully, from the perspective of the community that is most affected by it.
All the links are here. Please give them a listen before sharing your "hot take" on racism with the rest of the world.