I think people are concerned because both lemmy.ml and lemmygrad.ml are operated by the Lemmy developers. At a minimum, that means I'd prefer to avoid communities based on lemmy.ml and favor servers with less spicy admins.

There is, however a popular idea that software tends to reflect the values of its authors. Mastodon seems to be "Twitter for nice people" or thereabouts. If Lemmy is "Reddit for militant communists", that's a problem for attracting an audience beyond militant communists because most people don't want to talk to them.