In a remarkable turn of events, as part of a series of test cases on religious discrimination before the European Court of Human Rights, the UK Government is reported as having argued that "a Christian, or any other religious believer, “under difficulty” is not discriminated against if the choice of “resigning and moving to a different job” is not blocked." That is precisely the case I have argued against equalities rules (except in the cases I shall set out below) for many years (eg here, here, here (p18) and here).
If religious believers, or members of ethnic minorities, or elderly people, or women, or those with particular sexual practices (e.g. being married) can get a different job doing the same kind of thing, they are not harmed by being denied employment by those that would prefer someone more to their taste. Indeed, being able to use your property in ways you see fit (e.g. by purchasing the candy bars you like or hiring the staff you like) is a key part of what it is for your property to be truly yours.
Obviously many (probably most) firms will regard it as being in their interests to apply equalities principles to the hiring and treatment of staff. But equalities rules should apply, mandatorily, only to two workplace contexts. First, they should apply throughout the public sector. The reason is just the good old-fashioned concept of equality of treatment before the State. You should not face different laws or taxes or government employment conditions just because you are of certain ethnic groups etc. We wouldn't want Jews to face different laws or Catholics to be forbidden from being government ministers. The second context to which equalities rules should apply mandatorily is when there is monopsony hiring power. If a man, say, could not get another job doing what he does because a particular firm is the only employer of such staff in the region, he does not have the option to go elsewhere (as per the UK Government's argument in the ECHR cases), so can be harmed by discrimination.
Other firms should not be restricted. If, for example, a firm finds that by bad luck 90% of its current staff are women and it thinks its sales offering to clients would be improved by having a more mixed workforce, it should be entirely at liberty to set out to hire a man. If another firm has the theory that fifty-something women, working together without men or other age groups, produce higher productivity than in other contexts and as a consequence have low unit labour costs (they are cheap to hire, relative to their output in this context), it should be at liberty to test its theory by choosing only to hire that sort of staff.
So, the Government's argument is sound, and could be applied practically and usefully. But what would be unacceptable – indeed, intolerable – would be if such a principle were applied only to religious belief (indeed, even more narrowly specifically to Christian belief) with other equalities rules still applying even when other jobs were available. The Government is right to argue that there is no harm from discrimination when there is the option to get another job. But that applies equally to race, gender, sexual practice, hair colour, obesity, and any other aspect to which equalities rules are applied.