Downvoting a post most certainly can be trolling if the intent is that you do it simply because you dislike the person.

The pro-Hive whales downvoted to $0 three different witnesses simply because they are angry that they will support the Steem chain and move forward on this chain. That's trolling.

You can complain about definitions all you want, but the fact of the matter is that the people pushing for the Hive chain are here on Steem to bitch, moan and act like children. Power down and move on, people.