No you aren't. The intent is "Give Google the complete text, put up a paywall for everyone else". The fact that the technical implementation does not perfectly express this intent does not mean you can pretend the intent is different.
> The absence of security or warning thereupon is an implied invitation.
Nope.
> This is why, at least in the US, a warning must clearly be stated before trespassing can be enforced.
This is wildly incorrect when it comes to computers. The CFAA does not require any sort of warning in order to determine that a user has overstepped their authority.
This isn't even true in the physical world. Many states require notice that you're trespassing before you're criminally liable, but "many states" does not equal all states. And even in the states where this is true, the absence of a notice is not at all an "implied invitation", it just means you're not criminally liable if you weren't informed that you didn't have permission to be there.
> If you don't want me to access a given content then why are you giving it to me anonymously?
Because you tricked me.
The fact that you fooled me into thinking you're someone else does not give you the legal or moral right to the results. Neither legality nor morality is a game, where if you can just figure out the right loopholes you can get away scot-free. That's not how it works. Not in the real world, and not in computers either. The word that describes what you're doing is "fraud".
Just because it's easy to trick me does not make it right to do so. Your entire argument boils down to "if you didn't want to be tricked, you should have tried harder". That's not a moral argument. The ease of tricking me does not in any way affect whether it's ok.
As an analogy, let's say I'm a baker, and to celebrate my dear mother Alice's birthday, I decide to give away a slice of cake today to anybody named Alice that comes into my shop. I'm not a suspicious soul by nature, so if someone walks up and says "Hi I'm Alice" I'm inclined to believe them. I'm not advertising this anywhere, there's no sign saying "If you introduce yourself as Alice you get free cake", it's just something I'm doing. If you hear about this (say, you have a friend named Alice and she tells you about the free cake she got), do you think you're morally justified in walking into my shop and saying "Hi I'm Alice"? Sure, the damages are pretty small, but you're still lying to get something you know you're not entitled to, with no justification other than you want it.