Let me quote your source:
"What's more, while VIX is most often talked about on a spot basis, none of the ETFs or ETNs out there represent spot VIX volatility. Instead, they are collections of futures on the VIX that only roughly approximate the performance of VIX."
If you feel the S&P index is going to drop you can short ES futures, short SPY, buy puts on ES, SPX, SPY etc. You have many products that track the index.
If you think VIX is going to drop and you short VX futures, the VIX can drop and VX can stay up. VIX options do not track the VIX, they track the relevant VX futures. There are numerous instances where VIX moves one way and VX does not move at all or VX futures rise when VIX drops. Also VX futures have multiple expiration that move in ways that have nothing to do with VIX.
VIX ETFs are based on the futures.
I am not trying to be rude but when I say something and you all jump on me with supposed facts that are 100% wrong, then I come back with an answer along the lines of how about you do some research instead of coming across like you know something when the facts easily prove you wrong.