Problem is, Lotta, she was breaking the law.
I'm not sure she was. It would take an employment tribunal to sort it out. If one of the requirements of the job is to interface with customers, then someone who chooses to behave in a way which will alienate customers is not necessarily fit for the job. The employer might be bound to make reasonable adjustments, but customers aren't (ie, if you turn up to sell me stuff and refuse to shake my hand, I can either sling you out of my office or refuse to buy your stuff and you don't have a legal hand leg to stand on - discrimination legislation applies to the offering of services and to employment, not to purchasing decisions).
The argument that a salesman shouldn't be employed if he can't sell doesn't seem unreasonable, and even if the reason for that "can't sell" might pass as direct or indirect discrimination, to what extent is the employer liable to employ dead wood?
Sure, an employer who claimed all his customers were racist and therefore he couldn't employ black salesmen without losing money might struggle to get his case over at the ensuing ET (if it happened, which it wouldn't). The case of the hairdresser who got sued
But being black is a hell of a lot more fundamental to someone who is black than not shaking hands is to either being Jewish or practicing Judaism, aside from anything else because the vast majority of Jews wouldn't recognise this behaviour.
There's the case of the woman who lost an ET for refusing to employ a hairdresser who wore a headscarf, but (a) it looked like the complainant was trolling and (b) had she tried it on with a larger company they would have appealed and she would probably have lost.