I didn't say anything about Manchester. But since you've raised the topic:
Gatwick-Dubrovnik
Gatwick-Heraklion
Gatwick-Milan
Gatwick-Venice
Gatwick-Barcelona
Manchester-Sharm
Manchester-Dalaman
all in head-on competition with easyJet. Birmingham routes are self-evidently not competing with easyJet as they don't fly from there, but easyJet's introduction of a sixth daily flight on Gatwick-Barcelona as soon as Monarch appeared ought to have been something of a clue as to how they would react.
The Manchester-Venice, Dubrovnik and Milan routes just compete with Jet2 and/or Flybe instead. That's much better, isn't it.