So again, what if someone did not share your opinions? Is that any reason to cause an uproar? Not many in our society believe that morals are subjective, so let's not have that discussion. I often find myself unreasonably agitated whenever people tout higher moral ground that others, and issue is with the person's abuse of their fellow humans, not with the morals themselves.
I don't know much about other animals, so I try not to liken the furry type to our aquatic friends, but I will say I try to avoid those who don't share my opinions.
As I see it (if we're discussing Internet posts in general) there are three types of posts. One which touts what one is doing against the grain; be it keeping a Goldie in a five gallon or the like. One which is requesting help, as the person can tell the fish/shrimp are in distress for some reason. One which is proud of what one has and is asking for opinions or critiques.
I would reserve the word cruel for the first situation in some cases, but not all. I've seen just so many posts which claim they don't care what others say, they have something that works. Most of the time it is a fish in something far too small. Cruel is reserved for someone who thinks it is OK to not acknowledge countless people who offer personal experience and still continue with an act. It is cruel because at this point, I believe there is intent and neglect behind the actions.
One note to that is there are different levels of cruelty. I don't think a betta in a one gallon is cruel, but I do think a green spotted puffer in a one gallon tank is cruel.
A large part of the issue is the authorization to sell fish. You need none. I feel each person who sells another living thing should need some credentials to do it. That way all three of the posts I described would be sharply decreased.
In the other two situations I've encountered, I will try my best to help inform and guide, as I know I have something to offer people in distress. These are people who are reaching out to change what they're doing, and I try to be as blunt and helpful as possible. Sugar coating it would do nothing.
I always try to explain that I've made mistakes myself, and it is what makes me a responsible keeper of fish/shrimp.
This discussion is always an issue. It gets people heated up, as it is easy to get off track.