The stipulation is that it is woven ply (PEN or PET), not laminate. String sails are laminates.
188.8.131.52 Mainsail shall be manufactured from woven ply polyethylene terephthalate ("PET"), such as Dacron®, or woven ply polyethylene naphthalate ("PEN"), such as Pentex®. The spinnaker shall be manufactured from woven ply nylon.
The picture you show would not be a legal main under the current rules.