I accept the principle that discrimination or abuse should not be tolerated,
Good - well done.
but how do we bring about equality for some without denying it to others and exchanging one form of discrimination for another?
By looking at various aspects of society and identifying where there are forms of discrimination that sees some disadvantaged compared to others on the basis of a characteristic where a reasoned basis to maintain the discrimination cannot be convincingly demonstrated and where social attitudes have changed in support of removing the discrimination: for example, apartheid or restrictions on legal marriage.
Some may disagree on a personal basis but their preferences may be deemed to be less relevant than addressing the inequality on a society-wide basis, hence SSM is now legal where we both live, and especially where objections are based on fallacious arguments from authority where, ironically, what opponents regard as being authoritative (in this case 'scripture') isn't binding on the rest of us and, moreover, where entering into a SSM is easily avoided by those who do object to it.
Suppose the players in a rugby team are compelled to wear Stonewall ribbons during a match. (Bear in mind that Stonewall not only stands against discrimination and abuse but also stands for acceptance of the gay lifestyle). There might be one player who has experienced homosexuality but walked away from it. Should he be dropped from the team for refusing to wear the ribbon?
I realise that this is a thought experiment, but it does seem an unrealistic one bearing in mind the current problems football has with abuse and also the efforts being made to counter homophobia within the game - clearly football has its problems to solve - but I'd imagine that a player not buying into the ethos of their club is effectively dropping themselves.
Or suppose a teacher who has walked away from homosexuality refuses to teach that the gay lifestyle is acceptable. Should that teacher lose his job?
I think you might be using the term 'acceptable' wrongly: being homosexual is clearly 'acceptable' bearing in mind that it has been decriminalised (for consenting adults) and since homosexual people can now marry each other in many legislatures to the extent it is legally no different to heterosexual marriage. The personal background of the teacher isn't a factor here, since their fitness to teach 'modern & social studies' is a professional matter for them and their employer.
The key point is whether or not the syllabus to be taught involves recognising that homosexual relationships are an aspect of society-at-large, and since this is the case then teachers can do no other if the issue is contained in the syllabus that prescribes what is to be taught. However, in doing so they aren't promoting homosexuality any more than they are promoting a particular political party by discussing the various political philosophies that young people will encounter as an aspect of society-at-large.
I suspect you are conflating education about homosexuality being an aspect of society with the promotion of homosexuality - where the latter would rightly see teachers sacked.
And should heterosexual people who refuse to promote the gay lifestyle also be discriminated against?
Who is doing or advocating this?
All you are being asked to do, Spud, is not discriminate on the basis of the sexual orientation of another people: you aren't being required to approve, and your personal disapproval is your problem.
