The Fantastic Beasts and Where To Find Them actor made the remarks during an interview with ShortList.
The openly queer actor plays The Flash in upcoming blockbuster Justice League – thus becoming the first queer actor to play a superhero.
“I was told, when I gave that interview [that] I’d made a mistake,” he explained of his coming out in 2012.
“Folks in the industry, folks outside the industry. People I’ve never spoken to. They said there’s a reason so many gay, queer, gender-fluid people in Hollywood conceal their sexual identity, or their gender identity in their public image.
“I was told I had done a ‘silly’ thing in… thwarting my own potential to be a leading man.”
Related: Ezra Miller kisses male fan during heated embrace at Comic-Con
Ezra also spoke about the pressures of the film industry and the moments of doubt that followed his coming out.
“I don’t feel pressure. Pressure would only come from a dam, or a block. And when I came out I took the block away, removed the dam. I’ve undamned my identity in the world,” he said of being one of the few openly out actors in Hollywood.
“You’ve made a mistake’ is such a hard thing to hear. Maybe if I’d actually made a serious mistake? But not for this. I didn’t think I’d done anything wrong, though there have been moments of doubt as a result of those conversations.
“But… what they said was, in fact, ‘rubbish’. It is us to manifest the world we want to exist in. But we’re ready. Humans are ready.”
Ezra also revealed the comparison one former lover made of him: “I have been told by a few lovers that I resemble a baby dinosaur. I don’t know how to take that.”
Find out how in the latest this week’s issue of ShortList, available on Wednesday 8th November 2017.