This seems a very specious argument:
One of the purposes of food labelling is to tell us where the food came from and to what standards it was produced. That way I can decide whether I want to buy or eat it. The let's-label-halal suggestion was anti-Muslim in intent. Asking whether halal meat should be labelled as such is of no interest to me whatsoever as it tells me nothing about its quality or whether good standards of husbandry were used. When Muslims need to know the specific nature of their meat, they can and do handle that very well. The suggestion that meat should merely be labelled halal as a priority over stating its other welfare standards, as Keith and Iains suggest, is no more than a very badly-disguised attack on Islamic tradition.

When Halal meat was not easy to find, labelling it was helpful to Muslims, and not decried as being anti-Christian.
Now that it is becoming difficult to find non-Halal meat, asking that it be suitably labelled is "a very badly disguised attack on Islamic tradition".

As to "Islamic tradition", this would relate to dietary laws handed down to peoples living in much sunnier climates. The Christian tradition is based on the Bible (both New & Old testaments). We have (had) similar laws passed down from the book of Leviticus. We no longer follow these as they are not relevant to our climate and way of life.
That does not mean that we oppose others following these 'traditions', just ask that they do not impose them on everyone.