I was deeply saddened by Bishop Joseph Devine's decision to "pick a fight" with gay and lesbian Scots, although it was hardly a surprise to those of us who follow his increasingly erratic pronouncements.

His latest effort, a speech at St Aloysius' College in Glasgow last week, was filled with conspiracy theories, misinformation, and the rhetoric of hate. Bishop Devine should be ashamed of his allegation that gay people's presence at Holocaust memorial events is a political gesture aimed at creating "the image of a group of people under persecution". He seems to deny our right to attend such events.

About 100,000 men were arrested for being gay during the Holocaust. At least 10,000 died in internment camps. Several more were the victims of horrendous, bogus medical experiments intended to "cure" them. That is why representatives of the gay and lesbian community are welcomed to Holocaust Memorial Day events, and why Jewish groups and the Holocaust Memorial Day Trust have so firmly rebutted the bishop's comments. Bishop Devine should learn the lessons of the past and where hatred can lead. His talk of a "giant conspiracy", a "homosexual lobby" and "peril" will be sadly familiar to anyone well grounded in history.

I think the vast majority of Scots are proud to live in a society that has progressed as far as we have in the past century. The fact that Oscar Wilde was imprisoned for being gay, while Stonewall's founder, Sir Ian McKellen, was recently knighted, is a sign of how far we have come but Bishop Devine seems to hark back fondly to Victorian days. Would he like to see Sir Ian behind bars?

As for allegations of a "huge and well-orchestrated conspiracy" we're flattered, but the bishop is mistaken. There are 300,000 gay, lesbian, bisexual and transgender people in Scotland, and only 200,000 church-going Catholics. Which lobby has had the greater resources and political access over the years?

In further interviews, the bishop seemed bemused when accused of un-Christian attitudes. But his continued attacks on gay people seem to have little to do with the Christianity I was taught about or the sentiments of most Scottish Catholics. He must accept that his hateful comments are out of step with Scotland today a society where there is ample room for those of any faith or none. This does not mean there is a "war on Christian values" simply that we live in a society where it is not permissible to impose one's faith on others. I respect the bishop's right to practice his faith but he would deny me dignity and respect just because I'm gay.

It is tempting to ignore Bishop Devine's ranting and move on. But sadly, this isn't possible for thousands of gay young people. In the same speech, when asked by a parent what to do in the face of a child with a so-called "mission to become homosexual", he urged the parent not to "condemn" but not to "tolerate". He spoke of a child coming out as a "nightmare" for any parent.

Bishop Devine is the president of the Catholic Education Commission. His hard-line, ill-considered attitude means that gay children attending Catholic schools will have no-one to turn to not their teachers, not their parents, not their peers.

Three-quarters of all gay young people attending faith schools experience homophobic bullying, and they are even less likely to report it than gay pupils at other schools. Not really surprising when you have role models like Bishop Devine.

Calum Irving is director of Stonewall Scotland