It's bullshit because fansubs are illegal and fans are mostly using "it helps to promote the brand" as a justification when in reality it doesn't justify the distribution of pirated episodes and movies. Even if it does end up promoting the brand, fans don't get to decide when and how to promote something through illegal means.
And I'm not innocent either, I've watched fansubs for years and I am annoyed that they might go away but I'm also aware that that makes me an entitled fan who expects HD files for free a day or two after it airs in Japan.
Let's assume you wrote a novel and I pirate your book, translate it and release it for free and then I start telling people "I'm giving SageShinigami credit and promote his work". Would you be glad that I'm doing it and let a foreign audience discover your work or would you think it's kinda bullshit and I should cut the crap and stop stealing your property?
I mean, assuming folks are reading my work in other languages that I'm not offering it, then whatever. I'm not offering it in that language. Someone can take my articles, translation them into Russian, and as long as they're actually crediting me and not passing it off as their own work, whatever. And I'm not talking in abstract here, as my work is readily available in English.
Alternatively, if I want to actually produce my work in Russian, then I'd expect them to stop and go through legal means. But if you don't
give consumers legal means...
Again, this is why I bring up game archival, which is the area that changed my mind. Up until the SNES Classic came out, for example, Star Fox 2 was only available in ROM form. Period. That's Nintendo's legal right. But does it actually make it right? Probably not. (See also, fangames, which are technically illegal, but... ) Another good example is Macross, which wasn't even legal in the US until recently. Wuxiaworld operates in the middle ground, translate a very wide variety of Chinese works, licensing the ones they can and removing books as needed by request of the license holder. (One holder even just purchased the translations, and moved them to their own website.) Or the big three consoles in China, which for a long time were illegal imports only.
TL;DR: If you aren't offering the work in a legal manner for the consumer, then you cede that ground. Not legally of course, but I doubt you're doing anything to help the community around it. You're largely just saying you don't care. And many markets and mediums have made great strides in bringing that content to new markets. The key is
availability.