I agree that they should not be kept the way they normally are. But it can be a slippery slope when you go down the cruelty to fish road. When is any fish kept in an aquarium properly housed? We can set any cut off line for the appropriate number of gallons and tank footprint for any given fish but most of us will never come close to giving them the kind of space they would have in nature. I can argue that most of my fish live longer in my tanks than in nature so I am actually doing them a service. But most of them will never reproduce so I have deprived them of their most basic reason for being alive. I have been keeping fish for a long time and will not likely give it up but if you follow the Betta in a cup thinking far enough most of us just have a slightly bigger cup and should give up keeping fish.