So you openly admit to using a misnomer....why?  Why use it?  Is it supposed to sound like it represents a larger segment of the population than it really does? 

Because it's not actually a "majority".

It's a misnomer because the phrase itself gives a misleading interpretation.

I've never come across any of those stories. Any sources?

I didn't have to.  I'm well aware of it's use and history. It gained popularity under Nixon as a way to make the non-voting conservatives sound like a bigger group than they were.  Exactly like Trump does.  Everything with him is the biggest ever or larger than reality when the data doesn't back it up. 

And even under the auspices of a being a misnomer, it still doesn't work when he says it given the facts I just laid out.  He didn't bring out any people that weren't already voting.  In fact, as a percentage of population, fewer Republicans voted him than they did for any recent Republican candidate except Romney...and just barely at that. 

So not only is the phrase a misnomer, it was popularized by a crook and falsely being used by Trump. 

Also, your definition, "a large portion of the population that doesn't voice their stance with Trump out of fear" is even weirder.  If anything, Trump supporters are not afraid to speak out about their support.  So, not all that silent.  And no, those who are quiet about their support, are not the majority of Trump supporters. Maybe a Trump supporter in the middle of San Fransisco might be quiet about it but they damn sure aren't anywhere else.  Further, it would be ironic for them to be quiet given their 2A support and denigration of the snowflake, safe space needing mentality.

Please see:

You are under the impression that the definition of "silent majority" overrides the definitions of "silent" and "majority" and therefore it isn't a misnomer.  That is not the case.  

Phrases can be misnomers if the intended meaning doesn't match up with the definitions that make up the phrase.  

In other words it's a misnomer because this:

1.) It doesn't exactly cover it, but it does cover the case where a phrase doesn't match 

For example tin can is a misnomer because they are not made of tin.  Just like in this case silent majority is a misnomer because it's not actually a majority.  

"a wrong name or inappropriate designation.  The name "Greenland" is a misnomer, since much of the island is covered by a massive ice sheet."

https://www.merriam-webster.com/dictionary/misnomer

 2.)  How do you think misnomers work?

If there were tons of those happening all the time, it would be a national topic of conversation and Fox News would milk it for all its worth.

If there were tons of those happening all the time, it would be a national topic of conversation and Fox News would milk it for all its worth.

If you actually do research you will see how much more risk there is in being a "Conservative" in heavy "Blue" areas than there is risk in being a "Liberal" in heavy "Red" areas.