I guess technically 'if you try to' means also abusing unsafe, so in theory he's still sorta right. Every time I see someone ask a question about transmute on IRC I shiver a little.
But yes, Rust is way, way, way better in this regard.
The difference is safe-by-default languages force you to turn off the safeties before they will let you blow your own foot off. C++ doesn't believe in safeties since (at the time the language was designed) it introduces an unacceptable delay between you wanting to pull the trigger and your target and/or feet blowing up.
That's not Rust's philosophy. Rust is memory-safe, period.