I'm thinking like this.
It's a Fender licensed replacemenet neck. It's supposed to go on a real Fender. If the neck is good enough to be a Fender neck, why can it not have a Fender label on it? I don't think Fender has special magic machines which makes anything they create 10x better than other companies, and I bet no one would be able to tell the difference between a Warmoth and a Fender neck. After all, Warmoth is making them to Fender's instructions.
Sure, selling it as an "authentic Fender" might be lying a bit, but you could do that with any kind of neck. If you put on a Warmoth you're at least selling a really good neck.
I don't think it's a big issue, people get scammed for worse things than a brand name.