I thus consider all dogfooding unethical that is not done by somebody who has, or is provided with, a lot of influence on the product.
Apple doesn't use it's most mass-market product, the iPad, to develop the next iPad. But it does use Macs, probably even where they're slightly worse than PC's. If some kind of developer at Apple really needs a Laptop with 64 GB of RAM they probably can't get away with it without a very good justification.
This does, however, have objective benefits as far as company image, esprit de corps, promotion, etc.
But Apple might be a special case.
I guess it comes down to whether you're building just a tool or a lifestyle image.
If you're building a lifestyle product, then sure homogeneity or self-promotion has a huge objective value to the company.