If a machine has a Vne then you should be able to operate it (with due allowance for the Density Altitude on the day using the RFM) up to that figure, without having to take special care or avoid light turbulence in case it falls apart.
If the helo is unsafe at those speeds then the certification was wrong and the Vne and Vno should be revised downwards accordingly.
Of course that doesn't make Robinsons as competitive or attractive as the opposition so doubtless much pressure was exerted on the FAA to accommodate the certification - perhaps like SAC and the S-92's very remote likelihood of oil loss from the MRGB.
Yellow arc now added to ASI with mandatory reduction in VNE in turbulent conditions, but I take your point.
I hope to be in something more substantial before long, but I will steadfastly refrain from badmouthing the Robbies.
I think when first certified the inherently more pronounced risk of mast bumping in the lighter and more powerful R66 was not necessarily a known quantity.