Global warming dropped from use because it is inaccurate (or more precicly is too broad to be useful). While the global temperature is increasing, there are places that see a decrease. Usually this is due to either changing rainfall patterns (ie, former deserts that now get rain) or changes in ocean currents (eg the potential movement in the current that keeps the UK warm). Climate change is more accurate for people in those areas.
Semantics aside, you seem to have missed the point. This group seems to doubt it is happening at all ("so called" in this case doesn't mean they disagree with the terminology - instead they seem to doubt it is occurring)
The point is that it's broad in a specific way that makes it easy to misinterpret. Global average temperature increase may not yield local average temperature increase, and the reasons can be complex. Having to first explain that to people that are seeing the opposite of what global warming seems to be saying is a road-block to useful discourse.
Semantics aside, you seem to have missed the point. This group seems to doubt it is happening at all ("so called" in this case doesn't mean they disagree with the terminology - instead they seem to doubt it is occurring)