Since you have felt the need to apologize for ethnic, racial, and gender prejudice that may or may not exist within your legacy products, might I suggest the following statement rather than the one that appears on DTRPG and DM's Guild. It will not only protect you and those who play the game, but promote an ethos that has existed since the very beginning of this hobby and that has welcomed players from all walks of life:
Seeing that Dungeons & Dragons has been in publication since 1974, we are acutely aware that there are a variety of things contained within legacy products that some might find offensive. From the beginning, Dungeons & Dragons has entertained millions of people around the world, regardless of edition, adventure module, or campaign setting. Since 1974, and especially since WotC released the OGL in 2000, the game has invited players to change what they don’t like about the game. We at WotC firmly stand with players from all walks of life and encourage everyone to play the game the way that brings them the most joy.If you insist on warning people about content that may or may not exist in your legacy publications, I believe the above is a better representation of the game and the people who play it.
In contrast, the warning label currently placed above legacy products utterly fails to do both. Until such time that your current statement is removed or changed to better represent the game and the people who play it, I will not be purchasing any of your products and I will actively encourage others to do the same.