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.
My DD and most of her friends co-op or intern by choice therefore they usually graduate in 4.5 to 5 years. GT is a great engineering school and the graduation rate is a reflection of that- students have options like research, VIP’s, internships etc and they want to take advantage of those opportunities, not because they cannot get their classes to graduate or a reflection of the student body. My DD asked if she could graduate in 5 years because she wanted to do some semester-long internships and take just 4 classes while she did some cool research and engineering opportunities offered to her every semester. Since those things provide the hands-on engineering that she loves and makes her very marketable for jobs, we were okay with her taking longer.