Misunderstanding seems to be widespread about both the mechanism and function of the futures market and the causes of the problem. Arbitrage brings prices into equality between markets for related items.
Volatility is thought of as the variability or range of prices.
The problem perceived is that greater volatility in the futures market causes a price discontinuity between the futures and stock markets, which in turn encourages arbitrage, the ultimate effect of which is to transfer the volatility from the futures market to the stock market. Actually, arbitragers reduce volatility on the exchange where prices have gone out of line. Arbitragers step in to buy or sell against the direction that prices are moving, and in so doing they act to slow the movement of prices. To be compensated for this service they take the opposite side of this trade on the related exchange. Thus, by this action they introduce the volatility that they had acted against in the first market into the related one.