89% of the country has cable TV. If main stream media is liberal, how come FOX News is the highest rated news show on cable?

Maybe people just enjoy hate watching it, I know I do..

Because the claim about MSM being Liberal is based on dislike of liberals much more than on the articles published by one or another news-source.

Because Fox is fair and balanced  (jk)

Because it is the only channel that has conservative commentary.  Every other TV news outlet, cable or broadcast, is liberal.  Conservatives have one TV  source for conservative commentary, so of course their ratings beat out the others.  Easy math. This post was edited by Thriftymaid at October 23, 2016 2:46 PM MDT

Your data is wrong, and misleading.

Cable penetration is at around 80%. The latest census data indicates that there's 124.6 million households. Broadcasting and Cable's latest data indicates that "pay service" penetration (cable, DirecTV, Dish, etc.) has dropped to just around 80% at 99.44 million households as of late and continues to be in a steady decline. In fact, somewhere around 85% was the peak a few years ago, no where close to the 90% that you state. (On the flip side of that is that "streaming" delivery of various media services is very much on the upswing.

Keep in mind too that all the traditional "liberal" TV broadcast media outlets not only have cable distribution, they ALSO have an "over the air" presence and reach virtually 100% of households in the USA. FOX News is only on the pay services like cable. (None of the FOX O&O stations or affiliates carry FOX News, yet, probably due to contractual agreements with the cable companies. But with that decline in pay services penetration I wouldn't be surprised if they didn't start to show up on O&O and affiliates sub-channels as soon as that penetration number crosses some threshold on its way down.

Given those facts, that makes the statement that they're the highest rated news show on cable meaningless when compared to the entire range of possible viewership. One would need to look at all the numbers (things like ratings, HUT's, PUT's, shares, "cumes", etc. over different day-parts and broken down by a variety of viewer characteristics like age and gender) to derive any meaningful information. And that would apply to pay service penetration, over-the-air and streaming for ALL the media service you refer to; data that you have omitted for some reason.

I doubt it.   That is like the rumor that the Enquirer is the most widely-read newspaper in the USA.  Maybe, I doubt it. 

Fox represents conservative viewership in the only channel that is conservative in its reporting.  Liberals spread thier viewing among more than one channel.

If there are a dozen choices for democrat propaganda and only one choice for republican propaganda and the country is divided by half then logically the one choice for republican propaganda should do very well.
However the highest rated cable TV show will not be seen by even a small fraction of people who see a mildly popular youtube video. The medium is becoming obsolete. The numbers for a channel like CNN are now so small that you can have more viewers making a video where a cat plays with laser pointer.