This past week, my Facebook news feed showed a shared item that claims Confederate soldiers of the U.S. Civil War were declared as “U.S. veterans by an Act of Congress”.
Not exactly. In fact, most of this claims is false.

Snopes.com explains that this is mostly false.
This item works as social media propaganda because it appears to cite what sound like legitimate sources for the information (an appeal to authority). The item also appeals to patriotism (U.S. veterans) and the use of transference (Congress said they are U.S. veterans so therefore, they should be treated the same).
However, the alleged Congressional acts either do not exist or refer to something different. The alleged “last Confederate veteran” who died in 1958, was a fraudster who was not an actual veteran. In reality, the last actual Confederate soldiers died in 1959.
This is just a propaganda meme that is mostly not true, but sounded convincing to many.