All sorts of enthusiasts. Some people just want to grow plants in farm tanks and sell them. Some people want to have the nicest looking hardscape. Some want a jungle. Fauna, in all cases, may simply be optional beyond cleaner critters. Some may be only interested in adding a particular aesthetic to a room. I don't think anyone has the right to stand up and proclaim that the way they approach the hobby is any better than how someone else chooses to do so.
This seems like a harsh accusation of fish abuse and maybe I'm completely misinterpreting it. I had the same question on a split-lighting schedule. Asking the question is a testament that there is concern for doing the right thing. I want to optimally enjoy and view my tank when I'm in the room. But I would like to know if there is any detriment to either flora or fauna with a split-lighting system. If there is any detriment, then I wouldn't want to do it.
There is a dimmer system that turns the lights on/off gradually so there is no shock to the fish. This is the reason I'm responding to this thread.
In my first reply, I did let the op know they had asked a thoughtful question.
My post wasn't directed at the op certainly or anyone in particular though one poster did prompt this response that I've been thinking about on and off recently. Maybe this is a topic worth discussing. I could start a new thread.