The important issues in this case were highlighted in the first posts;
Established Easy pilots know that there is a limited amount of money to pay salaries and therefore to ensure that they continue to receive their well established terms and conditions they are happy thast a scheme is in place that is not going to overstretch that limited resource especially when times are hard and thereby are only too happy to see a system in place where new entrants remove as little as possible from that limited amount of money.
It's called "I'm all right Jack". and as posted early in the debate they turn their backs on or give a cold shoulder to the new entrants - not because they really dislike the way they entered the industry - it has been the practice for decades (how many of us remember Hamble closing) but because they are embarrased by the fact that it is clear to the world that they are maintaining tyheir terms and conditions in difficult times thanks to the fact that new entrants cost the company less.
There is nothing different from other industries - were agency work has become the norm or even the aviation industry - go ask a NATS ATC what happened to the new entrant terms and conditions in the past 20 years and you will have the exact same picture - new entrant Ts and Cs drastically reduced while established ATC's get increases (clearly paid for by ther new entrants)
One does not need a legal basis to see what is happening - just the willingness to seek change.