I've also experienced instances where entire biographies, translations, images, and more have been copied to other sites without attribution, particularly on platforms like Ancestry.
While I acknowledge Kathie's comment that complete control over the information once it's online is challenging, I believe in being vigilant about having the content removed when needed. I routinely submit takedown requests directly to sites like Ancestry, and I've found that the content is typically removed within hours.
However, not all content reuse is negative. Genealogy is about discovery and information sharing, and I'm supportive of content reuse if it is attributed to WikiTree. For example, if the content includes the profile the information was taken from (which already includes the names of people adding the information/content), it helps to advertise WikiTree, which I see as a positive outcome.