If I open the SE2717H/SE2717HX User's Guide page 11, it does show =

So we know that the monitor itself supports 75Hz. But the computer video card and the HDMI to HDMI cable must also support 75Hz. Using HDMI from the computer to HDMI on the monitor, if you open the monitor OSD (On Screen Display) and the bottom resolution states =
Resolution: 1920x1080, 60Hz

That means the monitor is getting that signal from the computer. There has to be something in the computer video card control panel to send the 75Hz. The monitor menu only reflects what it is getting from the computer.

If I try to set it to 1920x1080 @ 75hz it says the display does not support the frequency.  It says the maximum in the monitor settings (if I press the buttons on the actual monitor)  is 60hz.  It is hooked up to a new video card via the hdmi cable that came with the monitor.

What happens when I try to set it to 75hz

http://imgur.com/9ndrhtc

http://imgur.com/IQP7zR8

http://imgur.com/9ndrhtc

Here are some pictures of my issue.

Then you need to test this monitor and the same HDMI cable on another system to see if the issue follows the hardware.