As @MITer94 said, that’s the 4 year graduation rate, not the overall graduation rate. The engineers that I know at GaTech have all taken 4.5-5.5 years to graduate - but that includes a full year of (paid) work. For example, I know 2 who worked at Siemens in Germany for a year (at a real salary), another who spent a year in Tokyo, and several that worked in the US. So, yes, longer time to graduating- but not all classroom, and the jobs they walked into when they finished were amazing.
Make no mistake, though: GaTech engineering is serious work.