As everyone knows, it is not just as simple to get the hours and assume an automatic jump to the LHS. There are many potential slips along the way, and an FO is at the most vulnerable period of his career when he is awaiting his command. One slip in a base check (LPC/OPC) at this stage can be pretty disastrous and mean a couple of years more in the RHS. That is the same the world over and not just at easyJet.
These adverts seem to suggest that easyJet, for the obvious reasons of financial prudence and avoiding clogging up their already bulging training system, need to recruit current Airbus FOs to go straight into the LHS. I believe there is a precedent here in that it is exactly what happened in a number of cases with their 737s.
I cannot imagine that many current Airbus FOs with other companies would risk going to easyJet without the promise of an early command as an inducement. Suddenly an Airbus type rating with current experience has become a very saleable commodity, however frustrating that must be to the current 737 FOs at easyJet. There is no doubt that for FOs who are willing to take the risk of leaving their current company there are some great opportunities - or so it would appear!