"only" is a strong word. Should be used sparingly.
One of the most blantantly basic of concepts is that volume is comprised of TWO elements, each with opposing opinions/agendas.
Every amateur zit that's buying into a rising price on rising volume is disregarding that............someone is selling.
The distinction is the buyer is assuming fresh risk whereas the seller is willing to incur a tax event from a host of most of motives such as little Susie needing braces or an ax flush with inventory.