I think the problem is that the game officially supports the noob chat bubble. If some players consider it harassment or as an insult, the game featuring that chat bubble might confuse players that it's ok to call someone a noob. The noob term and the noob taunt is confusing to both victims and the taunters. Some may overtake the term of the noob.

This isn't unique to era. It's seen in a lot of competitive games. The usage of the word noob often happens when the player dies, a particular player is doing terrible at the game, or a player is using a weapon/class that is considered to be beginner friendly. Most of these factors are what players identify as traits of a noob. Unskillful, inexperienced, and "new" to the game. What players know buy don't want to admit at times, is that everyone is or was a noob.