This is basically true for any sailboat that has its shrouds out on the hull/deck joint. Three things prevent using a larger sail:
1) Any sail larger than 110% LP would have its leech run into the shrouds.
2) If you try and run the sail around the shrouds the sheeting angle would be wrong. Typically best around 8 degrees, having a genoa track out near the gunwale would make for a too wide angle for effect windward work.
3) The spreader tips are very wide on these types of boats and would stick into any genoa you tried to wrap around them.
But I would not worry. The rigs are generally designed for good performance with the sail area of a jib and a big mainsail. The only point of sail they suffer on is a close reach in light airs. That's what a close reaching spinnaker is for!