This is just my observation on it and I'm not bashing anyone but I can see why some would be irritated with a discussion like that. The post was pushing a Kickstarter for a restaurant (even though it would be train themed) on a model train forum. $0.02 on it.
Well, I completely support the Muffin enterprise, and hope their restaurant gets off the ground (although maintaining it long-term in a little town is another issue altogether), but strictly speaking (and as a devil's advocate), this view is probably correct. Personally, this isn't a big deal to me at all, but at its core this is advertising seeking money to open a restaurant. The fact that it has a train name, or is located near a train dealer, is beside the point. It is a restaurant. The idea that the Muffins are nice people (as a number of folks have opined), and are good to work with (as I can attest), is also beside the point. I wholehardedly support everything they're doing (I just wish they were doing it closer to me!). But again, that has no bearing on the issue.
If someone wanted to seek money to open a gas station in town, so people driving to a train dealer that is in the middle of nowhere can buy gas, would it be OK to promote a funding drive for that on the Forum? Would calling it "ChooChoo Gas" change anything? How about seeking funding for opening a convenience store with an ATM so visiters can get money to buy the toy trains?
This may seem silly, but it points out the difference between supporting a train dealer and its products, and promoting another business that sells something completely different. How far do you stretch the meaning of "it has something to do with the hobby?" In this case, in its essence, this is a money-making venture to sell food to customers, and it's using the Forum to get funding for a private for-profit enterprise. It's not a "feeding the hungry" charity.
Possibly part of the problem here stems from confusion about whether you characterize the Muffin's business as a museum, or as a train dealer. If it were strictly a museum, perhaps there would be less objection. If it's seen as a train dealer that happens to have a nice store layout (which most dealers have to promote the sale of trains), that's something different. If this were strictly a museum with a restaurant, located away from the train store, that might be seen in a different light.
Or what if another Forum sponsor (or ten of them, for that matter) decided to do Kickstarters on the Forum to raise money to build new toilets in their train stores to better provide for their customers' needs? That's not even selling something, and it's located inside the store. Would it be OK for the Forum to serve as a platform for funding drives for something like that? Where do you draw the line? Just something to think about, for the contrarians who like to argue.