But it is harming someone else in a way, they only want you to read it if you pay for it, there will still be bandwidth costs to cover for people who bypass the paywall, some might argue that in some paywalls, the content is already sent to your browser anyway but that's a whole different story.
It's the same argument for piracy, "if I make a copy, I'm not taking away the original, so I'm not stealing", which is just a lie to tell ourselves to feel a bit better at the end of the day.
I agree it's the same as in piracy, and I do the exact same there - pay for what I can, download the rest.
Regarding the bandwidth costs, those are absolutely negligible, since the methods for bypassing the paywalls either only fetch the text (e.g. http://outline.com) or cache it on other servers (e.g. http://archive.is).
It is definitively not what they wish, but not complying with someone's wishes is not harming them.
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On that last point, while I don't take my moral code from the law, I note that it agrees with me; for example, even if you have a contract with a guy to build your house, and you say your want a certain brand of pipes, but he ends up using another, you're not entitled to anything. Unfulfilled wishes are not harms.
It's the same argument for piracy, "if I make a copy, I'm not taking away the original, so I'm not stealing", which is just a lie to tell ourselves to feel a bit better at the end of the day.