Fun with Firefox.

[Moldran]

Would you say you had the right to tear down advertisement posters on the streets, because you don't want to watch them? Or are you saying that you insist upon the right to receive content while refusing to help the one providing it to receive some compensation for the work?

This is a completely inappropriate and misleading comparison. Tearing down advertisement posters would be equivalent to breaking into advertisement servers and sabotaging them, not to blocking ads on your own machine.
What you do on your machine is not some advertiser's or web hoster's business. Of course you do have the right to block any ads from web pages while still receiving regular content.
Which data you accept onto your machine is solely your decision. If a content provider does not want you to receive his content without receiving advertisements, it is up to him to ensure that his content is not send in these cases.