
I don't get sniping these are foreign novelsmanga being translated to english. Both are translating them by their self the ones "sniping" didn't take the raw version from the other group. This stories don't belong to anyone but the creator and I don't think they have permission from from. But thanks to both translators because I love this story.

It's because usually the team that was working on the series has already started scanlating the next chapter, which means that all the work they did was for nothing and they have to choose between doing the next chapter or still finishing the chapter they're working on- basically it's a mess.
So usually the polite thing to do would be 1) not pick up a project that hasn't been officially dropped before asking the team about it or 2) as @chiss above said, work together on the project (but then there's the scanlation quality issue).
HOWEVER there's a thing that most recent scanlation teams tend to forget, it's that this is pirate work and the fastest gets the spot. Period. I have been, as DnAS said, "sniped" before and while it's certainly not enjoyable, there's no need to make a scene about it. You just work faster and release before the other group. Or you make a bet and scanlate one chapter out of two and post it before them as (petty but enjoyable) payback.
I don't know what you're talking about but do what you're comfortable with. Thank you for the back to back updates.