Bull. Ryanair is giving up to 35 captains and up to 50 F/O's the option to take up unpaid leave this winter, simply because a part of the fleet will be grounded due to lower demand (edit: apparantly it's not due to grounding aircraft, so I'm wrong there). It's not forced, it's simply for those who are interested in it.
That's only 85 people max and they're not being fired, they're just going on holiday to Florida.
Why would you lay off 600 people if you have an expanding fleet and route network? Yes, just like other airlines Ryanair is feeling the pressure of high oil prices, but it's still growing and growing means MORE employees, not LESS.