Quite possibly, as a broader Language Act has come into force since 2003, but since Arriva seem to be quite happily providing the service of their own accord anyway, I doubt that's a problem for anyone.
Yes, it is in a sense. In the same sense that, say, providing the NHS or indeed subsidising the railways is politics. In this case, the Welsh people have democratically elected a government that is implementing a policy
the public widely supports. That's how politics works (or at least, should work!). You seem to be implying that the political aspect is somehow wrong or improper, but I just don't see it like that.
I don't know much about the situation in Scotland, but there seems to be
similar high levels of support for Gaelic provision there too.