Wrong wrong wrong. Across the board wrong. First of all 4K is not he same as UHD, UHD is a video format, 4K is a RESOLUTION. This is absolutely 4K. And secondly frame rate is 100% dependant on the soirce. How many different ways can I put this for you to understand it? There would be no 4K picture for FILMS better than what this produces.
2160p resolution is one part of UHD. That is what you call 4k.
4K is part of UHD. UHD is bigger than just 4k. When people go into a best buy and say "I want a 4k tv" they don't care about the exact pixel numbers, other than knowing the buzzword "4k", they care about adherence to the standard. Adherence to standards is important to people so they can be confident that their new BR discs will be compatible, and their new consoles will be compatible, etc.
Adherence to the resolution alone is stupid at best, and deceitful at worst. Pardon the pun, resolution alone isn't the whole picture.
I know that frame-rate is dependent on source. I'm not saying everything HAS TO play at that higher frame rate, but it must be supported. Plus there is plenty of source material that has higher frame-rates that 24fps. Some new blockbusters are higher than 24fps, games, sports.
I'm saying, to be "UHD compliant", which is what the FireTV claims to be, it must support up to 120fps. Again, I'm not saying it HAS TO show everything in 120fps (which seems to be how you're reading it), but it has to support it.