The statement is technically correct. Shrinkfile on a log file does not move information around in the log when truncateonly is specified. The problem is that it's easy to assume from that statement that when TruncateOnly is not specified then information is moved around in the log, when it isn't.

I suspect that was added because the way it was written in old Books Online could be read that ShrinkFile with truncate only didn't work at all on a log file, which was also not true.