When you buy stuff in a store, the items remain the property of the store until you pay. If you take them without paying then you're stealing. This is firmly enshrined in both morality and law.
When you view something with ads, they send you the stuff first, on the hope or assumption that you will later view the ads. No property changes hands at any time.
No, it really isn't. This may surprise you, but it's possible to point out flaws in an argument without making any statement about the merits of the conclusion.
