Absolutely needless cruelty should be avoided, period.
However, the needs of the hobbyist are sometimes at odds with the needs of the pet, and some balance must be struck. With the hobby attracting every variety of person, including extremists and the perpetually clueless, it's a fertile ground for disagreements on what that balance should be.
And it will be that way until the end of time. Not limited to animals either, I could give you a list of people I know who I think shouldn't be raising children, and I'm sure most people could do the same.
I originally got into planted tanks solely to provide a better environment for fish, though now I will take measured risks with fish in order to keep the plants healthy. Is that wrong?
We do in fact have several bettas in one gallon jars. That is the simply the most practical option for now, until we can arrange for better accommodations. However, we did add live plants, plus an unused shop light and ferts so the plants could perform their function. Easy and cheap enough. The bettas have excellent water quality, they're active, and enjoy playing with the plants and other toys we give them. Is it still wrong to keep them in jars?
A couple months ago, we were contacted by a fellow running an NY animal rights activism group, who wanted to secure permission to use some of Stef's animal artwork as a logo for his group. We are both animal lovers, and were initially inclined to say yes. But a quick check of his blog revealed the following statement, "it's my goal to eventually acquire enough money and power to make veganism and the Animal Bill of Rights LAW". And that according to his Bill, this would outlaw use of animals for ANY purpose. Food (for humans or other animals), entertainment, milk, wool, etc. In addition to some suggestions that several recent and notable natural disasters were retribution for us wronging animals, doled out by a higher entity. We respectfully declined, not wanting to be associated with his ideals; to which he essentially replied, "Then what kinds of animal torture do you support and want to be associated with? I'm sure your customers would like to know." Is what he wants, or us declining wrong?
No easy answers here.