UK needs a strong British airways that does a decent job in terms of supporting business and tourism (inbound)
Trust me on this; neither IAG nor any company in the Group, including British Airways, gives a toss about the welfare of business and tourism in the United Kingdom now, let alone when we leave the EU where, of course, IAG is registered, except to the extent the UK's economic state impacts on the Group's revenues.
Certain other airlines, notably Virgin, are at least British-owned and do a better job of supporting UK business and tourism although that is not their primary concern, any more than it's BA's.
Others exist only to take people out of the UK to their holidays.
To recap, the primary airlines in the IAG are Aer Lingus, British Airways, Iberia and Vueling. Apart from its name, British Airways is no more and no less British than the other 3 airlines. They exist to create increased share value and dividends for the Group's owners who include, of course its senior executives.