Actually I see nothing official on this site that says it’s for collectors. My observation suggests that only the Vintage Omega forum is collector-heavy and the others are more balanced.
It’s true that the OF is not exclusively for collectors but it is predominantly for watch nerds, who display most of the obsessive traits of a collector, even if they only ever acquire one watch.
-and I think you can expand the collector-heavy moniker to all of the vintage sections of the forum (Longines, UG, Seiko, etc)
Most people don’t buy and sell watches like a collector might.
This poses a broader question of who buys vintage watches and why - and who sets the value?
Second hand stuff generally gains a premium value if it is deemed ‘Collectible’ - initially and eponymously by ‘Collectors‘ but let’s just call them ‘buyers’ for now to avoid any unnecessary distractions about what is a Collector.
Collectibles buyers can come in various guises - such as, those who hoover up anything and everything, those who only buy the best examples available and those who simply have a interest in having something desirable.
Band-wagon jumpers aside, it’s the second category of buyers who essentially set the achievable sales price of an object but as they say ‘a rising tide lifts all boats’ and that is why we see so many ‘less than perfect’ examples of watches here for premium prices.
It’s true not everyone buying vintage watches thinks like a collector, however, when a new member pops up and asks (an admittedly collector-biased sub-forum) what do we think of the watch and is it worth the asking price, they’re going to receive collector-focused responses.
Ultimately, it’s their money and their choice but as long as the poster gets straight advice they can then at least make an informed decision about how they spend their hard earned cash.