Facebook did nothing to disabuse people of that notion. It never said 'Come build a page with 10,000 fans, and we'll show maybe up to 15 percent of them some of the posts you make, some of the time, using a formula that only we understand.'
Imagine if you hired an emarketing company to send a email blast to 10,000 subscribers once a week. A couple years later you notice that nobody seems to be responding to your blasts, so you ask your emarketing company what's up and they tell you 'oh, we only sent those emails to 1500 people because we saw that not everyone was reading every email.' You'd fire that company, right? Because they promised you one thing and delivered something else.
That's where Facebook is right now with the millions of small businesses who believed that initial pitch. And that's why these folks are so mad: Because Facebook lied to them -- either recently or in the past. It's yet another bait and switch from a company that appears to have perfected that technique.
Personally, I am always amazed at the difference between using Facebook on the Web and Facebook on my various mobile devices. It is striking. On the Web, my news feed is pretty severely throttled -- I see posts from maybe a dozen people on a consistent basis, with rare occasional visits from random members of my 1100 friend posse. On my iPad and my Windows Phone, I see stuff from people I forgot I had friended. I see a huge range of stuff, some of it completely uninteresting to me, but at least there's some variety.
So my question to Facebook is, why not give us the option of seeing everything and let us decide what's noise and what isn't, like we do on Twitter? Why should Facebook decide what is interesting to me?
I feel compelled to also note that on the mobile apps there are no ads. No ways to share, no ways to promote posts. And I suspect that is why Facebook hasn't bothered to apply the same algorithms there -- they aren't monetizing their mobile feeds. Yet.
Remember, as Yoda once said: There is no lie, there is only true.