The only arguments against seemed to be sentimentality; a misguided belief that other, divisive, cultures should be fostered and nurtured; and Welsh nationalism.
To which it could be claimed that the only arguments in favour of your position are consistent only with being a bigoted cretin.
Or the abuse and the arrogance could be dropped and things could be looked at more reasonably. In which case it would seem obvious that attempts to accommodate the Welsh language (so to speak) are quite reasonable. Bilingualism is the order of the day anyway; there are no monoglot communities left now and no prospect of bringing them back. So why get angry?
A majority of people in Carmarthenshire claim to be able to speak Welsh to some level. There are actually only a handful of wards in the county there were a majority don't understand the language at all, and the only one where it's a large majority is Laugharne (which is south of the Landsker). Parts of Carmarthenshire - the Amman Valley especially - are almost as Welsh speaking as Arfon.
And, of course, most people in Wales who don't speak the language have no problems with Welsh place names.
He's just an idiot, ignore him.