I really can't see the issue here, either you're willing to pay for the content or you're not. I don't understand why people get their dander up over something that is optional. If URD feel that they would like a financial remuneration for their many hours of effort, then good for them. If simracers want to purchase this content thats their decision, if you don't agree, that's you're decision. No need for a war, theirs too many of them happening today as it is.
As my Granny use to say, "If you have nothing nice to say, then it's best to say nothing at all.
Payed mods were inevitable, and considering how much content the major software companies like Codies, EA or Activision sell as DLC, I think the simracing community has done well to go for as long as it has to avoid the profit hungry direction most industries end up in once they become heavily commercialised.
And be warned, the commercialisation of our hobby is coming, the fact the FAI have put cease and desist orders out on FAI sanctioned series in mods rings alarm bells for me. The official racing bodies are starting to take notice of the popularity of racing sims, and they can see a large profitable niche area, and they stand to make more money from game sales than selling a few car licenses to a few devs I would think.
When this happens, and it will, I for one will be glad that mod teams like URD exist, because their payware content will be cheaper than the hungry multimillion dollar dev companies content will be, just look at how much DLC Activision has released for the Call of Duty series and thats on top of the initial game purchase of $89 (thats AU dollars) how much do you think they ask for their DLC's, a bit more than 9.95Euro I think.
I'm all for helping the little guy and I will buy this mod, as I feel the content is worth the asking price and no doubt with the hours of enjoyment I will get it's a no brainer for value.
Just an old guys opinion.
Cheers.