"FR crews are based in Budapest for immigration and customs purposes while at the meantime are Dublin based for inland revenue and social security duties?"
And a lot of Wizz Air "employees" are based in BUD (and elsewhere) throughout their network, whilst paying "Swiss Tax" on their earnings - and neglecting to take care of tax liabilities nearer home.
So, I don't think Ryanair are any worse than Wizz Air in this particular instance.
As for how, or why Ryanair is being singled out, you can ask are their Chickens coming home to roost? For so long MOL has belittled and bullied others, that it is a joy to see his "plans" not working smoothly.