...those researchers will have to work very quickly in order to avoid being scooped...Such a sloppy approach will lead to hasty results and incorrect conclusions to the detriment of the entire field.
If it turns out they were wrong and you can prove it with the years of research you've been sitting on then GREAT! You get to publish a paper detailing how the idiots that didn't do their due diligence completely botched it. Maybe a public shaming teaches them a lesson so they're not so quick to "scoop" people just because they can, or maybe it teaches the publication to not green-light folks not doing the work. At a minimum it puts a spotlight on the ne'er-do-wells so they get side-eyed till they shape up. This is good for the field, not detrimental, highlighting the difference between the solid, reliable scientists (and publications) and the posers.
If it turns out they were correct and you can prove it with the years of research you've been sitting on then GREAT! You put the new knowledge on a secure footing, becoming the "shoulders of giants" as it were. And, not for nothing, you can probably still get in a few digs about the scooping party's lack of rigor. (See the shame argument above.) Publications that truly care about quality work and not just headlines will publish. This is good for the field, not detrimental, again highlighting the difference between the solid, reliable scientists (and publications) and the posers.
If it turns out they were both correct and did good work then GREAT! This is good for the field. No crying because they scooped you. If you really care about the state of the field then prove it by being big enough to acknowledge they did good and then do some introspection to see if you can find out why you were dragging ass while they knocked out some solid work so quickly. Maybe you're in an academic malaise and you need to wake up? Maybe you need to step up your game, find another gear?
The 'not good for the field' argument is bs. What they really means is 'not good for me'.