That’s part of it.
Anti-islanding protects the folks working on the high voltage lines.
If you backfeed a transformer that normaly steps down 2400/7200/12470 to 240 Volts, it will
put that 2400/7200/12470 on the line its primary side is tied to. A lineman performing a repair
isn’t likely aware the line is live. (although proper training says treat ALL lines as live)