I used hyperbole and a little inference, but it's usually the same things. People see someone asking for something and panic because there's something that may compete with what they want. It's really not up to you to manage the devs' priorities. Promote the things you want appropriately if it bothers you.
More variation in height is not grounds for a new race nor even a new clan. People love to throw around lore but don't really know what it is. It's not an absolute statement on the limits of biology. Lore is history and generalizations about race and culture. The descriptions of Miqo'te clans make several statements that are just not reflected in the character creation. Things such as ear size and tail size are the same for both. There will always be limits but there is nothing wrong with people asking for a little expansion on those.
It's usually just a couple different issues: "If this happens I might not get what I want" or "I don't want to see something I don't like." It's fine to have an opinion but don't act like people are trying to take something from you when they are not.