And to provide a concrete example: Rage Against The Machine demanded that Rush Limbaugh stop using their music on air. Because those performances were not licensed, they qualified as an illegal performance of the work. But RATM certainly didn't issue that cease and desist because they were concerned about lost revenue.
Copyright is violated when a work is distributed or reproduced (or performed or... there's a few categories).
If I take a website, duplicate it, then publish it myself, I am engaging in copyright infringement.
If another person comes along and views my website, they are not engaging in an illegal act. It's the act of distribution that is infringing, not the act of receiving.
In your example, if a publisher creates a website and distributes their content, that publisher is exercising their rights to distribute that work. But there's no strings attached, there. Unless I sign some sort of binding contract that stipulates that I must view ads in order to receive the content, there is nothing in copyright law that says I'm in any way stealing or breaking the law by blocking those ads.
And if such a contract was in place (say, a click-through ToS... though whether those are enforceable is a question), my blocking those ads would be a contractual violation but it would not be "theft" in any meaningful sense, nor would it violate copyright law (it would be a violation of that specific contract).
So no, they are not "inherently the same thing". A publisher publishes their content. As a receiver of that content, I can do whatever I wish with it, including censoring/redacting the portions I don't want to view. Similarly, if I bought a newspaper and cut out all the ads before I read it, no reasonable person would consider that "theft".
This is because Ruby inherits it's approach to flow control from Smalltalk, while Python comes from a C/Algol-like heritage.
In fact, Smalltalk takes this much further, such that basically all flow control (including if-then-else) is handled as message sends (e.g. if-then is just a message sent to the Boolean object taking a block as it's argument).
The downside is the syntax can feel a tad clunky. The upside is incredibly simple and consistent language grammar, while making it trivial to create new flow control mechanisms since the language has all the tools baked in (primarily first class blocks).