Its what I was taught in biology at school.. {4 decades ago.}. so yes I have to agree that could be wrong...
Eating lots is irrelevant evidence is well though... I m sure you didn't crush them to smithereens.
I suspect the true figure is between about 10 times what I said & 10% of your equally ridiculous figure!
As for evidence , here some about peach/ almond kernels that contain the same poison {Admitadly in greater amounts. }
Delena Tull (Edible and Useful Plants of Texas and the Southwest, 1987) wrote …
“Human cyanide poisoning most frequently occurs from ingestion of the seed kernels inside the stony pits [of peaches, plums, apricots, cherries, nectarines, etc.]. The classic poisoning story tells of a man who relished apple seeds also in the rose family. He saved up a large number, then ate them all at once. It was his final meal (Ricciuti 1978). In recent years health food enthusiasts have encouraged the eating of apricot seeds as a source of laetrile, allegedly to prevent cancer. Though a single apricot seed probably can be considered safe for an adult, a man who ate 28 died (Michael Ellis, letter to the author, August 1986). A small child reacts to a much lower dose of a toxin than does an adult. As few as two to five apricot or peach kernels can be fatal to a child (Ellis 1978). Cyanide has a very low lethal dose, and death can occur rapidly. [...] A few other vegetables and fruits should be treated with caution. As long as you eat lima beans in the United States, you need not worry, but if you travel outside the States, beware. Lima beans, Phaseolus liminensis and P. lunatus, contain the cyanogenetic glycoside phaseolunatin, which also converts to cyanide in the body. Cyanide levels of lima beans in the United States have been monitored since World War I.”