And almost no one is actually saying this - the people who ARE claiming this are people accusing others of making that argument when they're (mostly) not.
What they're doing is way past irrelevant details. And fans are not happy, that seems quite clear from the reactions so far. Whether or not that fan unhappiness will matter is another story - as people have pointed out, they can well just make a WoT-inspired show that isn't too beholden to the original plot, and that could (at least conceivably) be financially successful. Maybe the fans won't like it but that doesn't have to matter if enough other people do like it. The problem, of course, is that generally shows like this tend to rely on fans to spread the word to non-fans, and vouch for the quality of the show. If instead fans are telling non-fans to stay away, that could have significant impact on the performance. But nothing is set in stone, and Amazon will, of course, know better than to immediately go "omg everyone hates this!" and exacerbate the spiral. So we'll have to wait and see what happens.
For me personally, the show is pretty much dead. I gave it a shot, I hated it, that's that.