I'm not sure if this point was brought up in the thread because I haven't read it, but since the purpose of glofish was initially to detect pollution in certain areas, would the people that are against glofish rather they use harsh chemicals to test the pollution or use glofish?
You might be thinking that the chemicals aren't that harsh, and even if they are, it's a small amount. Well, the chemicals themselves may or may not be detrimental to the environment, but the process of either manufacturing or extracting the chemicals would probably add some pollution to the environment. Also, even if it's just a small amount, it will add up over time.
I assume the environmental impact of raising a bunch of glofish is less than making all those chemicals to test water, so what do you pick, genetically engineered fish, or chemicals that impact the environment?