I'll reserve judgement on what's considered 'acceptable'. However, in legal terms, Irish Travellers are defined as an ethnic group and, as such, receive protection against race discrimination, race being one of the nine protected characteristics in the UK under the Equality Act 2010 (excepting NI where the DDA 1995 still applies, albeit with some supplementary legislation). That same protection is not afforded to the 'working class' (whatever that means these days) given that class is not a protected characteristic under said legislation. To paraphrase, we might think the law is an ass but it's still the law.