Nothing here is changing VNQ, this is just somebody making another index out there. The index that VNQ is based on (MSCI US REIT index) is not changing.
Someone is making an equal weight REIT index from only the REIT stocks in the S&P 500, and there will be another sector for REITS added to the major sector list (tech, healthcare, financials, consumer discretionary, etc). Before REITs were in the financial sector funds, and apparently they are going to separate the two. The dividend for the financial sector will drop because of this, that's what the article is referring to.