From reading what you've said, your parents seem to have an issue with animals...even YOUR opinion of them.

Because you live at home, under their roof, being supported by THEM, you'll just have to respect that.

I wish I could offer help, but there really isn't much you can do. You have differing opinions, and I'll give you they are pretty hostile regarding animals...and you aren't in a position to do anything about it.

Just enjoy the animals you DO have...maybe volunteer at your local shelter? Work at a petstore?