Base expansion
Last time FR were making a hostile takeover bid (ie not the most recent failure, but the one before) EI were operating 320s out of Aldergrove. As I'm sure any readers of this thread from Belfast will testify, Aldergrove is a bit annoying for them being so far outside the city. Meanwhile FR were operating 738s out of Belfast City with reduced loads due to MTOW restrictions from City's short Runway, and as a result were making a loss. So of course they pulled out of Belfast altogether.
During the lull between the two most recent bids, EI were free to spend some of their cash again, so bought some slightly smaller aircraft (a319s) and moved to Belfast City.
FR's single type aircraft fleet was unsuitable for EGAC, however due to EI's Independence, they were able to make some changes and exploit this. As a result BA do not have a monopoly on the Heathrow route ( which they would do without EI even if FR do go back ). So an example of how having them separate from eachother is better for the consumer, no?
And as for EI chasing other airlines off routes years ago, yes they did,and it was bad for the public. Difference is, EI did it 30 years ago and were finally made to stop, FR are doing it NOW.