When i started in the platform i commented more than i posted because one i still didn't have enough followers yet and 2nd almost 45% of what is earned back then was from upVotes I get from commenting from whales down to Redfishes like me.
It became a natural habit to me not because I was looking for votes but because I am an avid reader and by commenting I add further to teh discussion about the posts as well as to make sure that the author knows someone read his/her work and took time to comment.
I didnt have a lot of SP and yet I wanted to reward people who interact with me. Know with a slider due to delegations I am able to upVote comments although it is a measly 0.01 cent because I am just a red fish.
It is true when you comment back and give an upvote you are rewarding the person who took his/her time to reads yours. The from follower they can be an engagers.
Now regarding trollls as much as I want to downvote I save my VP for upVotes.
Same as you. I would rather be encouraging and spreading my upvotes rather than flagging but that's just mine.