The masked Eren made frequent rounds in Agora. He could be considered as an ill-famous showman.
The butcher's appearances on Agora generated a massive amount of hype. He was mainly the target of criticism. And unsurprisingly, he was fine with it.
He didn't let compliments or criticism bother him and did what he did best: creating unrest.
Eren knew that he and his followers were getting targeted. However, the Elder Ichor faction was not completely defenseless.
Unless they slipped up in Agora or openly supported Eren, their identities in Labh Salem were protected. Eren also improved his Fiendish transformation with subsequent test projects over the years, enabling his followers to unearth more of their potential while allowing them to revert to their normal forms with no residual defect whatsoever.