Most people don't get any problems with First Officers at Gatwick, and the standard is not any different now than it was a few years ago. In my experience, if you treat people with respect, in 99.9% of cases they will respond well. All FOs understandably want to be captains, and there is absolutely nothing wrong with that - if they have reached the required standard, there are few companies in the world that can offer the promotion opportunities easyJet can.
However, that is the sideline conversation here. It is absolute nonsense that easyJet 'need' DECs at Gatwick - they do not and there are dozens of perfectly good FOs queuing up to be Captains. As long as there is one qualified and capable FO in easyJet who wants to be a captain at Gatwick then there are no grounds for employing a DEC in his place. What on earth BALPA are doing over this I do not know - very little by the sound of things. No one has an issue with easyJet offering jobs to Monarch guys - but they do have an issue with them taking the commands of current FOs around the Company. The Monarch guys can join as FOs like everyone else at Gatwick and take their turn in the queue. There is a rapid promotion system available and they will be captains again in a couple of years at whatever bases have vacancies at the time. What Monarch pilot would have accepted DECs there? You've guessed it, not a single one. This is nothing to do with Monarch pilots' abilities - they are clearly top people and highly competent at what they do. This is all about leasyJet pilots looking after the interests of their own colleagues, because no one else will. It is absolutely not the responsibility of the easyJet CC to look after Monarch's pilots - their sole job is to look after the pilots in their own company.