I agree. But at the same time, it's all a matter of perspective.
The way I see it is if you take any betta home from virtually any pet store (save for the ones who actually give a crap about what they do with their bettas), it's a rescue.
My reasoning for this is that if you think about it, a few days or weeks down the road if they're not picked up and taken home by a caring owner, even the healthiest, most beautiful betta is more than likely going to come down with SOMETHING. And at places like wal-mart, their employees and managers are not going to care what the fish has. Because at wal mart, rollbacks are more important. And fish are "just fish" to them. A few extra dollars in corporate's pocket.
I don't even want to think about what would have happened to my guys and girl if I hadn't taken them home. Given they didn't have any visible health problems outside of color loss (Winston used to be grey/white), but it could have been so much worse.
Like I said, it's just a matter of perspective, and if you do see a fish in serious need, and you have the means to bring him/her back from the brink, TAKE IT HOME.
Winston~ Damian~ Twitch ~ Evans