This is fairly well covered in the lengthy topic at:
https://forum.inaturalist.org/t/agreeing-with-experts-and-research-grade/3718
and perhaps more directly in the topic at:
https://forum.inaturalist.org/t/changing-the-system-to-limit-the-ability-to-confer-research-grade-status/394
and comes up in the topic at:
https://forum.inaturalist.org/t/agree-button-on-identify-thumbnails/1597
and an associated feature request:
https://forum.inaturalist.org/t/remove-agree-button-on-identify-thumbnails-in-certain-cases/3040
The issue of the number to reach the arbitrary green label comes up often. The catch is that if the threshold is increased, then correcting incorrect IDs made by inactive or nonresponsive users becomes all the more difficult.