This is somethat that a lot of people tend to overlook, either because they don't understand how a hard drive works, or because they don't stop and think about it. Loading programmes, especially ones which rely on libraries, translation files, multimedia, etc... at other locations on a disk would greatly slow down a HDD in comparison to an SSD.
Contrasted with SSDs, which are pretty much random access devices, in order to read each of those files from an HDD, there are basically 3 time factors to consider.
1. Seek time. The time it takes to move a reader head to a specific track (ring of data on a platter). Assuming that there is only this read taking place, you can pretty much assume that the reader head moves from its current location to the correct spot on the disk right away. Things are not always this pretty, though.
2. Rotation time. On average, you will have to wait half a rotation for the correct spot on the disk to spin around to the reader heads. There may be algorithms designed to mitigate this by reading even as it waits. In case the read is large enough to span a significant portion of the track, it can append that buffered data later, but I don't know if this is done or not.
3. Read time. This is the amount of time required to read the data off of a single track, and can take up to 1 rotation of the platter to complete.
So while the GP has a point in that people need to be careful about what kinds of statistics they believe, he/she glosses over the fact that reading a single piece of data with an HDD is hardly a random access, constant time operation (or linear time for n pieces of data).