Rules and moderation

Regarding this post

I searched for explicit rules for this forum and cannot find them. Just to check what is considered inappropriate here.

I would prefer that if the content of a post is inappropriate and should be deleted, moderators delete the content but keep the post, adding some explanation of his decision. Same if some content is modified, to be clear that it’s not the original post.

I now explained what I changed in the post, I should have done that before. Sorry.
There were complaints about racism. At first I decided to ignore it, but at least 3 posts in the thread where continuing on racism instead of the original post. That’s why I decided to interfere.