It's not the consumer's job to make companies profitable. If their business model relies on people viewing ads when they don't have to, that's their problem.
I think that if a consumer is to be considered to be obligated to follow the ToS, they should be presented with the ToS /first/ , and also have it be of a length which is actually reasonable for a typical person to read.
A person should generally not (there are exceptions in e.g. emergencies) be expected to agree to something without specifically choosing to agree to it, and knowing what they are "agreeing" to.
I think it is perfectly plausible that everyone knows google, youtube, facebook, reddit, SO and other such sites rely on ads to operate. Yet people with adblock continuously use those services while blocking the business model which allows them to operate. It's not a case of loading a single page and not knowing what's there. You profit from those services every single day and knowingly harm their operations.
Ok so again, I personally don't use adblock, so I do not, by using adblock, harm their operations. I don't know if you meant "you" as in me, or "you" as in the rhetorical "you", but I wanted to clarify that, in case you meant me in particular.
Yes, it is true that one who frequently uses sites like google and youtube and such probably knows that those websites have ads, and rely on ad income to operate. This is separate from whether the person knows whether using an adblocker is forbidden by the ToS of the website. And I think this might be somewhere where you have changed what you are talking about when it is convenient to you? (which you have accused someone else of)
In fact, from the ToS s that I have read, I don't think I have ever seen one that specifically forbids using an ad blocker while using the website! At least, as far as I can remember. Forbidding intentionally making false ad impressions, I have of course seen, but I do not remember any ToS forbidding using an ad blocker.
So, case in point, I do not know that the google search ToS forbids using an ad blocker while visiting the site, and in fact it is my (weakly held) belief that it probably does not (but I could be wrong about that).
I don't think one should be considered to have agreed to a ToS as a contract if it would be unreasonable to believe that the person truly did read and understand the ToS. If a person can reasonably be expected to know that what they did was against the ToS, despite it being unreasonable to believe that they read and understood all of the ToS, then that could make sense for them to be held to I suppose. But I don't think that the average person can be reasonably assumed to know that the ToS forbids using an ad blocker (and, in fact, I don't know that many ToS s do forbid using an ad blocker. I don't remember any of the one's I've looked at forbidding it after all).
Unless one is specifically made aware of an agreement, I don't think they can be reasonably considered to have agreed to it. One cannot unknowingly agree.
I run ads on my website, and I don't mind if users run an ad blocker while viewing it. (Though, I suppose its not much of a business, so that might make a difference there).
So, to conclude:
I don't think most ToS s have clauses which forbid the use of ad blocking on the site.
I don't think one can reasonably expect a user to know that ad blocking is forbidden by the ToS unless they are specifically informed of it.
I don't think users who have not knowingly entered into an agreement to not block ads on the site are obligated to not block ads on the site.
It's not the consumer's job to make companies profitable. If their business model relies on people viewing ads when they don't have to, that's their problem.