Maxvorstadt: Well, the IE thing is not a thing of GOG alone.
Yep, there are many lazy or b-grade coders out there.
Windows has a simple ShellExecute command that will open the default program for a file type or web link. It is a very very simple thing to code for. It takes a bit more code and thought to use a non default browser, though I guess with IE it is a known location, seeing as it comes pre-installed, so not a lot of extra code.
And maybe there is an element of cost cutting too. Only spend time getting things to look right in IE, so maybe less coding overall, just poor pathetic browser support.
My view, is it is a crime for IE to run on my PC. So the fact some code for that deliberately is intolerable and disrespectful of my wishes.