I agree that what constitutes "dangerous conditions", at its lower limits anyway, depends an awful lot on the boat and skill and experience of the sailor. Most sailors on Lake Michigan consider 20 to 22 knots and 5 to 6 foot waves as to rough to go sailing even in a keel boat (of course this is absolutely not true), I think because these conditions make most sailors on the lake aprehensive and sailling would therefore not be any fun. I on the other hand, in July and August, have alot of fun in these conditions. I simply put in a double reef and go sailing.
Here is a true story. I decided to leave Mackinac City so as to get west to Grays reef before the wind picked up to the forecast 25 knots and then head South to Charlevoix. The boat is a Freedom 21 with no jib and the winds were light North going heavy North to 25. I power sailed with a full main and about 5 miles from Grays Reef I put in a double reef. I got to the turn at 10 AM , put up the chute and headed for Charlevoix (well almost as there is a little island I had to miss on the way). The wind picked up pretty good and the boat was zooming along. I admit that there were a few gusts which kind of got my adrenalin pumping but I enjoy the rush. Approaching the channel to the bridge I noticed a Coast Guard inflatable boat bouncing badly in the waves before going back in. The waves here were extemely steep 6 footers. We dropped the chute, headed up, dropped the main and in we went. Now here is the interesting point: the Harbor Master asked where we had come from and I said Mackinac City. His reply was "no way, the coast guard just came back in and said it was to rough out there". Was it to rough? I don''t think so.