I wouldn't own them.
But I'm not sweet on long-finned mutants, fancy guppies, flowerhorns and a host of other modified fish. If you like them, go for it.
I would like to see common plecos and other fish that outgrow tanks out of the mainstream hobby. Keeping them gets cruel. But if they were 'special orders' instead of easy, convenient mistakes for newbies, go for it. In large tanks, they work out.
I'd like to see intentionally deformed fish banned. They do feel pain if they have twisted spines, etc. Their nervous system is complex. Cruelty breeding is a real issue.
But there is no cruelty in glofish. The gene splicing doesn't hurt them. It hurts my eyes, but my eyes are sensitive. I have seen the beauty of wild fish. I fear that if glo species and fancy mutants take over the market even more than now, you might not ever get to see fish as they come from nature. My best LFS has about 75% "fancy" linebred, human modified fish now, and they are fish designed for sales. It would be a loss, in my opinion, if it became 100%.