You can opt out of that. Its explained right after what you have quoted.
> To stop future conversations from being reviewed or used to improve Google machine-learning technologies, turn off Gemini Apps activity. You can review your prompts or delete your conversations from your Gemini Apps activity at myactivity.google.com/product/gemini.
> To stop future conversations from being reviewed or used to improve Google machine-learning technologies, turn off Gemini Apps activity. You can review your prompts or delete your conversations from your Gemini Apps activity at myactivity.google.com/product/gemini.