Agreed.
I also usually think about the fish, and wonder what kind of life they would live being relocated after spending years in my house, with me, and my routine? A bit sappy I suppose, but I suspect that the stress could be quite significant for many of the larger more intelligent species, especially if rehomed as adults, and especially if rehomed to the hands of an idiot with terrible husbandry practices. I certainly would never consider doing that with one of our dogs. Some animals, including fish, might never bounce back from that kind of an ordeal.
It's interesting, at least to me, how some folks who preach about how best to keep a fish in captivity (size of tank, tank mates, etc) apparently have little issue with swapping out stock whenever the urge strikes.