I don't see how it can be "unfair" to attack a specific player in a game. And I can see a couple reason why you'd want to attack a player who isn't winning. Maybe you're weak, and attacking you is the easiest way to catch up with the winning player. Maybe the person thinks that he won't be able to catch up with the winning player, so he tries instead to secure a second place, and attacks you.
I remember having this discussion with a RL friend some years ago. He was pissed that I had bludgeoned him instead of the winning player. The reason was the second I mentioned (trying to secure the second place) but he told me that you never try to end up second in a game. Only try to win, and so only side with the others to beat whoever is on top. Maybe he was seeing things this way, but I don't. And again, I totally fail to see how it's "unfair". A game is a competition. Other players will inevitably attack you.Why they decide to attack you and not someone else is frankly unimportant. Maybe they have a good reason that you can't see, or maybe it's stupid on their part, but it changes nothing. It's still an opponent attacking you in a game, which is expected. There's no reason that I can perceive to be bothered by this.
To me, your complaint sounds a bit like "some players have a play style different from mine. I always attack the winning player, and they don't. So I take it personally and insult them for not playing the way I think a game should be played. Why doesn't BGA sanction people who don't play like me?" It seems to me that you're the problem, not them. It seems to me that the issue is your emotional reaction to something that is perfectly normal when people play games.
And to answer your last question : what do I do in similar situations? I do nothing. If it bothered me to be attacked in a game, I wouldn't be playing games. As long as nobody is cheating and it's within the rules, it's fair. Things don't always go the way you'd like in a game. Sometimes the die seems to be against you. Sometimes someone's strategy includes destroying you from the get go, and you never have a chance to advance in the game. So be it. You just start a new game. I guess that there could be some extraordinary situations when it could be a problem, say some guy harassing you and deliberately trying to join your tables specifically to spoil the games for you. But then you'd just need to block him.
