I see no reason for Feds to not have a Carrier similar to that of the Klingons. Feds will built anything if they see a need for it. I hope Cryptic does add one in the near future, if not, then keep posting about it until they do.
As for the hostility is usually from those who do not like when people come up and pose old or new ideas that would change the game from what it already is or what it already favors. I would just suggest ignoring it and if it really get bad then reporting it. There will always be some people or groups that think they know better or are not nice to new people.