No it doesn't. It comes with 1GB of memory, and memory is always "internal". I think you meant it comes with 16GB of storage. And of that storage, several GB will be taken by the OS partition.
It has 1GB of
RAM (Random access memory), yes.
But he's talking about storage memory, a microSD card, which has nothing to do with RAM.
The phone has
internal 16GB of storage memory and is expandable with an 'external' microSD card (you put it into a slot inside the back of the phone's case). He's talking about potentially being jipped out of this 'external' microSD card. So again, nothing to do with the 1GB of RAM.
As far as the 16GB internal memory goes. The EVO LTE has 2GB partitioned for app usage and the rest (besides what's being used for the operating system, etc.) is free for photos or whatever else you add like music or movies, etc..
If you run out of app space with the 2GB partition already in the phone (that's a lot of apps most people likely won't even use) either delete ones you don't use or most likely they'll simply start going onto your microSD card (if you have one inserted). Personally, I don't plan on adding many apps. Besides calls, texts, and being my alarm clock; I mostly just use the internet, email app (I use mail.com), eBay app, my bank's app, and I only plan on adding a few more beyond that, since the phone already has mostly everything else I'd normally use (calculator, navigation, weather, listening to music I add, etc.).
Edited for wrong use of 'ROM'.