Sourceforge intentionally breaks hotlinking.
Like many other distributed cloud services, they choose a mirror based on location so it's all dynamically generated.
It also provides them an opportunity to offer viruses and spam on the download page which generates revenue.
From what I understand many projects commit the packages onto repos si direct linking works.
The current process has bee discussed though and seems like it suits our needs for now until we dedicate hosting.
It is rather unfortunate that free services tend to go downhill like this over time, but its just the trend of the internet.
If we want direct links, we pay. That should be expected this day in age.