I don't think that anyone with any competent knowledge is suggesting that the work level and difficulty for an undergraduate degree is on a par with the ATPL. Those who might do so surely have not done both and are speaking from a position of some ignorance.
However, the typical uni degree subject examination is touched by that wonderful old feature known as the "zero shifting theorem" whereas the ATPL is a hard line examination with reasonably tight time limits (in the main) and a relatively high pass mark.
I read aero eng and had subject results ranging from pass to HD and I did the old ATPL/SCPL subjects. As well, and as required/tasked, I teach all the various licence subjects these days. I know which exams were the harder to pass on the day. Nothing much to do with technical content and all to do with examination pressure on the candidate.
Note that I don't suggest that this should change for the pilot exams as part of their purpose is to put the candidate under a bit of stress. So far as content is concerned I could put a reasoned case for raising its level of technical rigour but that is another discussion over a beer or two.
There is no aim to make engineers (or any other discipline) of pilots. As John Farley put it, the pilot needs to know the ins and outs of putting the theory into cockpit practice (although it might take some time to locate the thread in which he made that observation).