Not necessarily true
"It has become common practice to brief the FCTM procedure for bounced landing in the last few years. I have never heard any body say "oh, and by the way: Autothrottle TOGA mode won't work". That would be because nobody has thought of it before. Same as prior to the Asiana crash nobody had thought about the effect of indirect mode change. And half of all pilots still don't understand it."
Actually, my company teaches press TOGA, push throttles and keep pressing TOGA until it engages. We teach this precisely because GA will not engage if the squat switches are on.