The only download software I used was the DownThemAll Firefox extension, which has always been real good. It works on all sites I’ve tried it with, it’s a very customisable interface, I don’t really know what you mean by not copy-pasting links but you don’t gotta do that.
You’re not likely to find an exact copy of the software for another OS, wine probably is your best bet if you just want IDM in Linux form.
It’s already been proven that piracy is a causal factor in more sales. Any self-interested dev should be promoting piracy of their game.