Unless you're personally donating large sums of money to Mozilla, you need to stop whining about their innocuous, non-spyware ads that are easily removed.

Your alternative isn't some hypothetical "pure" browser. Your choices are Microsoft spyware, Google spyware, or presumably some Chinese spyware. Or Firefox, imperfect though it may be.

There are now only two viable rendering engines left in the browser world, and Firefox Gecko is one of them.