This type of review bombing is actually against steams terms of service for reviews in the first place, they've stepped in a few times now to hide campaigns like that, I expect they will do the same with this one. Basically it'll keep the recent review metric but, it will hide the reviews from the historical and the overall metric. So worst case out of this will be it has a negative recent reviews for awhile.

your last sentence is actually the exact reason they implemented that policy and they moreorless quote it in their forum post where they talk about how the new system works