Why is the acute toxicity of glyphosate itself relatively low in humans?

Humans lack the specific enzyme pathway that glyphosate inhibits.

Glyphosate's herbicidal action is specific to an enzymatic pathway found in plants but not in human or animal biology. Because human cells do not possess this biological target, the glyphosate molecule does not trigger the same destructive chemical reactions that it causes in plants. This lack of a target mechanism contributes to the relatively low acute toxicity profile of glyphosate, meaning that exposure to trace amounts typically does not result in serious systemic poisoning.