I would choose not to call a dog it but I do not want to take a peek at its genitals.

I always call a dog by it's sex but it's not abuse to say "it". It won't hurt the dog any. They listen for tone of voice more than anything else anyway.

I would call the dog by the animal's sex. But I wouldn't say that it is cruel to refer to a dog as an it. As mentioned, the dog isn't hurt by it and if your tone is friendly then they wouldn't really care. But I still would rather not call a dog an it.

No, but I personally don’t call a dog that. I call the dog by their name, or their sex.

I don't say it, but it's not causing any harm to the dog. Also "it" sounds like something someone who doesn't care about dogs would say.