That doesn't extend to animal cruelty. And before you claim that it's not cruelty because it's not cruelty under the law, what people who advocate banning are saying is that it should be considered cruel and inhumane. It's understandable if a pet owner can't always control their cats' scratching - not every cat is perfect, but of course we love them even if they destroy our furniture and claw into our shoulders so we don't want to just get rid of them. But there are alternatives that do not require you to put a cat through that kind of pain, fear, and risk. Saying "we should be able to do it anyway because we own them" is like saying beating a cat severely is something we should be allowed to do if they don't listen, when there are plenty of humane alternatives to teach a cat how to act.
Did you know that cats walk on their toes? The same toes you're advocating the free amputation of? Imagine having part of your toes amputated, and then being forced to walk on your toes instead of your whole foot. That's what it's like for cats. Many studies (unfortunately I'm having trouble finding more recent studies, but the process hasn't really changed) put the risk of complications as high as 50%. Imagine you have 2 cats, declaw them both. You have a very, very good chance that at least one of them will experience post-op complications: these range from lameness to hemorraging to necrosis to abscesses to bones shattering to the claws painfully growing back to nerves growing abnormally, causing lifelong pain for the cat. Some of those will require extra painful surgeries to fix.
There are no benefits to the cat that declawing gives them, that vinyl nail caps do not. The only difference is how much the person cares about their cat over their own convenience, since declawing is a one-time thing and nail caps have to be reapplied. But heaven forbid they actually put forth effort for the cat over allowing it to undergo a risky, painful surgery!
This may be tl;dr, but declawing literally disgusts me. My family has owned dozens of cats (over 20 at one time, for years), and not a single one has been declawed. There are alternatives, and if you care enough about your cat then you will look for them.