Whitepaper plagiarism is a sure sign of a scam project. Any project worth any amount of money would be able to write their own whitepaper without having to steal from others. There is no excuse. If you find any, you should open a new thread in the
Scam Accusations board to bring it to the attention to the rest of community.
One possible excuse for plagiarism, they have hire someone to write it for them and they didn't know that the one they hire just copied it somewhere else. It is s a valid excuse? I don't think so. If they don't have any reason to scam then they should get someone competent or at least try to check everything because releasing their whitepaper.