Honestly, I just dislike other people's dogs. They're off leash, aggressive, and slowly bleeding into every space. Having a neighbor that encouraged anxiety and barking was an exceedingly unpleasant experience.
That being said, I'm uncomfortable with the idea of animals being created for and existing for humans. The situation is definitely better than the livestock industry and there's also the complication that the pets seem to be happy and humans seem to be happier with pets. It would also be exceedingly cruel to take away service dogs from those that have them.
But, pet ownership is rising world wide. Given the demand, they'll be bred. Pet QoL is going up. Now that they're family, their environmental impact is going to grow.
Yes, rescues are better than the alternative. Spaying and neutering reduce harm. I wish that the default pets would instead be cold-blooded terrestrial animals and rodents. I wish pets were unable survive outside of captivity.
I think it's generally immoral to own pets and that if one does, one should strive to maximize the human happiness:externality ratio. It's a minor immorality, but the OP asked for controversial moral opinions.
Just a matter of time until this trailer gets made. I remember the Oppenheimer one and now that we've got the AI trailers, you don't even need an actual movie to use as source material this time.