You're doing the digital equivalent of saying "the pumpkins are right there for me to take, they were delivered outside for me to pick up and place in my car, for free. With no exchange of currency. I can just walk by the store and grab one and walk away".
In other words, you're ignoring both the legal contract (the terms of service) and the social contract (if everyone just grabs a pumpkin and walks away its obviously not going to be profitable and the company will stop offering it, we can only have the social 'nice thing' if everyone plays nice).
Just because its physically possible to do a thing doesn't mean the company consents to you doing it, or you deserve to do it.
You can easily litter. There's nothing stopping you. The ground is right there. You shouldn't though and you're rightfully called an asshole if you do.
If you applied your mentality everywhere, you would say "if you don't want me to litter in this National Forest, there ought not to be any businesses that sell disposable products within a 500 mile radius. It's not my fault you set this up for me to do so."