I have this to say. Almost everyone here has been downvoted based on personality as well as quality of writing. Because we're all flawed and have traits that will rub others the wrong way from time to time.
I've been subjected to many individuals on a downvote campaign. One spent months going through and downvoting almost every one of my writeups. One is still ongoing, it seems. It happens; no-one can please everyone all the time, and it seems that I offended some folk.
I remember talking to dannye about this, over a beer. I still consider him one of the best writers here and he would sometimes be flooded with downvotes, because in addition to being a great writer, he was also occasionally a spiky and outspoken critic. As a result he garnered some notoriety. Thankfully, the balance of things was such that his detractors were vastly outnumbered by his fans, and as a consequence his corpus has a high vote reputation.
Perhaps your friend has ticked off enough people over a long enough time that they suffer the reverse; that their personality traits have been sufficient to override the quality of their writing? Perhaps the community has spoken. Perhaps three times is no coincidence, but it doesn't have to be a conspiracy, just a community response.
This place is a community, and a community protects itself. Ever see a hornet getting mobbed by bees as it tries to get access to the hive? The bees act according to their nature in driving out one that is considered harmful to the community. They will either sting or smother it to death rather than see it cause damage. The voting system is a part of the hive's defence mechanism.
For my part, I love this place and in general, the people in it. There are people I met here I'd take a bullet for, they've become so important to me. Consider me part of the hive, stings and all.
Edit: Someone pointed out that that last sentence makes it look like I'm a part of some downvote brigade. I'm really not. That isn't how I work, and I've better things to do.