I don't know why people do this... Google provides Gmail and other services free of charge because of Adsense, don't ruin that by facilitating the removal of their ads...
Here's a great trade off, don't want to see ads in your email? Don't use Gmail.
This is why we can't have nice things.
Now, you don't seem to take into account the fact that this overflow of ads we have to face (more and more) on a daily basis actually encourages people to become active or passive ad-avoiders, decreasing then the income generated by ads. I clearly think this kind of business model is not viable over the long-run...
Now completely removing the ad using JavaScript also kills that CPM revenue.
These people are leeches. I see removing ads on a site the same way I see pirating movies... Don't want to pay for the cost of a movie ticket because they're so outrageous? Then wait for the movie to come out on DVD, get cheaper, and possibly hit the TV and watch it then... But don't go out and pirate the movie because you feel entitled to watching it free of charge.
Same thing with Gmail, or any service that is ad supported. You are not entitled to using that service free of charge... You are entitled to using it by enduring the advertisements. Removing them is costing the provider money without even recouping a bit of it.
You come to my site, watch a video or view a gallery of pictures or read a bunch of text, whatever... Still costs me money, If I make a penny off you, it's better than nothing... If I make a penny off every user who visits my site, and 100 people come, that's a dollar a day, $30 a month... Paying the bare minimum at least the cost of the VPS I run to give you that content... Completely remove my ads and guess what... I am now paying $30/mo and it's no longer feasible for me to entertain or offer you something without charging you for it... Guess what? Service gets shut down, and then you spend your time griping about how all the good free services end up shutting down and that you wish you could have donated or even paid a small monthly fee to keep it alive... But in reality, all you had to do was endure a simple Adsense block that wasn't even intrusive, but you felt entitled to view the content or use the service while blocking it... And now your service is gone.
The one way to ensure that anyone who uses your site will provide you with revenue is to make them pay for it. There's nothing inherently wrong with that: it has its pros and cons, like every other business model.
What I'm trying to get across to you is the idea that the morality of ads and ads blocking isn't as simple and clear-cut as you obviously like to think. Calling people who use ad blockers leeches won't solve whatever concrete problem made you post such a bitter comment.
Here's a question for you: is it okay for me to go to your site and then, after the content is rendered, use Evernote Clearly (or some other readability tool) to re-render that content without any ads?
If not, why? Is it because Clearly is another program and you drew an arbitrary line at using software instead of, say, covering parts of screen with paper?
On the other hand, if you answered "yes" to the question about using a readability tool, then would it be "okay" if I used some tool that behaves just as if the ads were being rendered, but it doesn't render them? I'm guessing "no", because that starts to sound unethical. So how about a separate extension that auto-activates a readability tool after the page is rendered?
In other words, where do you draw the line? Or better yet, can you draw the line as clearly as you thought and enjoy your moral high ground? Or should you try to be more flexible and realize that you can't really have it all and there are always trade-offs in every approach you might take?
Maybe it just boils down to a realization that "all complex ecosystems have parasites" [1] and it's not necessarily a bad thing.
Out of curiosity, where do you draw the line? Am I also required to read each ad? Purchase something from x% of advertisers?
I've been a Gmail user since it was in very early beta and I don't think I have ever read a single ad on the site. They're there - I apparently immorally trained myself to ignore them though.