Some Christians feel so "picked on" they are too scared to speak about their faith in public, a bishop has warned.
The Right Reverend Nick Baines, the Bishop of Leeds, said some secularists "have a problem" with religion being talked about.
And he warned that a brand of "intolerant" liberalism circulates in the UK which is dismissive of the Christian faith.
He made his comments after Theresa May said it is important people can talk freely about their faith following claims some Christians dare not speak about Christmas.
Bishop Baines told the Press Association: "Clearly there are some Christians who are concerned about whether they are free to talk about their faith in a respectful and appropriate way in the workplace.
"Equally, there are plenty of people who are not Christians who think that Christians shouldn't, or think there is an issue around it. I call it religious illiteracy.
"There are people who have been disciplined or threatened with discipline for talking about their faith even though they have been asked about it. Someone makes a complaint and says they have been inappropriate. This is absurd."
He added: "There is, amongst some Christians - this isn't universal - a sense of being a little picked on or beleaguered.
"I think if you claim to be open-minded and liberal, why are you so frightened of religious expression?"
The bishop said relations between different religious communities in the UK are good, but that some secularists are intolerant of Christianity.
He added that, at the more ridiculous extreme, this can end up in some people trying to strip the religion out of Christmas.
"The joke with all of this is that most people of other faiths have absolutely no problem with anyone talking about their faith. It's the secularists that have a problem," he said.
"It is a Christian festival. Are they going to tell Muslims they have got to strip Islam out of Eid? It's just ludicrous."
There have been a number of cases in Britain when Christians have been disciplined or sacked at work for expressing their faith.
Shirley Chaplin, a nurse, was switched to a desk job after she refused to take off a crucifix which hung round her neck, while registrar Lillian Ladele was disciplined by Islington council for refusing to conduct civil partnership ceremonies.
They both took their discrimination claims to the European Court of Human Rights in Strasbourg but lost their cases in 2013.
These stories spread and lead to some staying silent about their religion in public, Bishop Baines said.
And he warned that Britain has become a liberal society where some people believe you are only acceptable if you accept liberalism.
"And liberalism can become very intolerant of anything that doesn't fit its own parameters," he added.