I have seen this debated on here before re the fact that some organisers of sportives are commercial organisations making cash by "claiming" that the ride is for charity when in fact all of the entry goes to them - the Manchester 100 being particularly singled out. The follow on argument is that these are public roads so the right is their to use them, with many claiming to have made a charitable donation instead.
I don't buy this because the organisers are very clear about your entry fee and I am happy to pay it to cover the marshalls, road marking water stops etc.
In response to the no need to pay argument, I challenged people to make a donation to Christie's and was challenged back on whether I had, because none of my entry fee had gone to them either. I included a screen shot of my donation to Christie's but don't recall any of the none payers doing the same.
I think the people mentioned in the thread start should be bloody ashamed of themselves, commercial organised or not, this is poor behaviour. If you want to take advantage of their facilities then pay for it.
For the free roads idealists argument for events like the Manchester 100, then at least recognise the charity concerned and stump up a tenner or so directly to them, then your argument might be taken more seriously.