Sometimes advertisements are deliberately written to allow foreigners to be employed in preference to less well-qualified locals. Maybe for an injection of a better safety 'culture;' to keep a lid on wages, or whatever.
If they can't attract applicants with the exact criteria they seek, and depending on their desperation level, employers have been known to change the rules to suit.
If they can get applicants with the criteria they seek, then for those that don't have it, tough titties.
It is always the employer's train set.