I've heard that several times and I have no reason to believe it is untrue. BA weren't exactly the only culprits and even today, Lufthansa attempts to prevent frequencies of the ME3 in Germany. Bilateral agreements (more prevalent in the past) were in their very nature, restrictive to competition. LH also still seek to limit LCC activity in FRA.
Indeed, much of the criticism levelled by Rutan were/are actually relevant to most of the network carriers. Incidentally, BA were one of the first of that group of airlines to offer one way fares etc. By comparison, until relatively recently, KLM still stipulated the old Saturday night rule on it's cheapest fares. Again, the criticism is probably best levelled at the network carriers of old rather than just British Airways. But...again, the hostility among many comes from the fact that BA don't serve MAN much above the LHR shuttle.
You are right in saying that in the absence of a national network, the US carriers are that nations rail network, but the hub and spoke model is prevalent the world over and to say that having no national railway is the only reason that model works in the US is ridiculous. Where things changed in Europe was the LCC's and despite being based on Southwest, were different in many ways. Notably, offering non-stop services as opposed to Southwest which operated more like a Greyhound bus, stopping off at various places. The Brits embraced the LCC's and BA will have found it incredibly difficult to compete, at the time they offered a far superior service, a service that many weren't willing to pay, especially when considering the LCC's stimulated additional demand through lower fares, something BA struggled to do with the product it offered at the time.
When BA pulled its CitiExpress base at MAN and sold it to FlyBe, it did keep its code on flights for a while and I think perhaps its biggest mistake was to not then bring BE into the stable when that carrier was profitable. I would have adopted a hybrid BE/BA brand similar to HOP! by Air France.
But ultimately, the hostility towards BA, at least today, is because they don't really serve MAN and people believe that as the national carrier (which they are not) they should do. Hence the old "London Airways" mantra.