Unfortunately it is tough to ensure 100% compatibility with all types of GPUs. When you launch Lightroom on one of these Macs with two sets of graphics, the Mac switches to the Radeon 6750M automatically if you allowed it to be enabled in LR. Lightroom will list the Radeon 6750M because it's the more powerful graphics hardware that it is interested in (of course). But if you click the 'System Report' button, then click Graphics/Displays, you will definitely see both types of graphics listed if the Mac has both. Like you do, I see that About This Mac only reports the Intel HD 3000, and I am not sure why, since I have the Radeon 6750M active right now. On the MacBook Pro that you and I both own, the Intel HD Graphics 3000 is the integrated graphics, and the AMD Radeon 6750M is the discrete graphics. When no programs are asking for maximum graphics power, it should switch down to the battery-saving integrated graphics. Your MacBook Pro automatically switches between the two types of graphics depending on load and depending on if the preference setting 'Automatic graphics switching' is on (System Preferences/Energy Saver). Discrete graphics is separate graphics hardware with its own video memory, more powerful than integrated but also a bigger drain on the battery. Good enough for general purposes and is more efficient with battery power. Integrated graphics are part of the CPU module and take memory from system RAM. The higher spec 15' MacBook Pros come with two forms of graphics: integrated and discrete. Curiously, the LR prefs show an AMD 6750 Open GL GPU, while About this Mac shows an Intel 3000.

Turning off the GPU seems to have helped.

Lightroom cc mac