To Gen1 Guys, easy.
It's really that simple: You get mods for free, as someone others hard work, made in his/her free time. For own enjoyment, for fame and bunnys, for good of mankind. Pick your own. FC in his great post listed reasons many stick with Gen1, for some it's really hard to buy new series as digital download, some have old systems etc. BUT sticking to Series1 and bitching about lack of backward compatibility (which sometimes is really hard) is just mean. Sorry. It's modder's decision and kind of mod released if it can be used in both series. As example -my recent terrain mods around still should work in Gen1, as I stick with BMP and TGA formats for various reasons -backward compatibility isn't my top priority- so making them usable in Gen1 is really simple and goes down to simple Ctrl+C Ctrl+V 5 min of work.
But as time goes by and the series evolves, it's for good of all of us afficionados, among other reasons, to support TK by buying his new titles.
It's really pointless to stop evolution. You can't. All you can achieve is to annoy or offend someone who spend sometimes months doing something brilliant for you, as Monty CZ pointed out.
edit:
I've read whole topic Henrik linked, and I find it disgusting...
To make some DDS conspiracy theories..? Why isn't it yet starred and flagged on beforeitsnews or abovetopsecret? jeeez guys.