Why do people always try to make out 1940s Swing or big-band as if we're rugged or grungy like 1950s Rock N, Roll?

I mean 40s Swing and Big-Band just are slick and elegant by nature.
1950s #Rock 'n' Roll #Jive classes for starter/intermediate levels are taught in #Glasgow each Tuesday
1950s #Rock 'n' Roll #Jive Classes starter/intermediate taught by Professional teachers tonight in #Glasgow . 182117 - 99.074074074074
To continue; furthermore on the hype tip: I roll & rock, rock & roll, jazz & pop, rhythm & blues, dance & fusion, b…
Caveman invented Rock N Roll. The First Rock n Roll band were called 'The Rolling Stones' #FakeCavemanFacts

On the hypothesis that it was the rock which followed them, just as Paul says it was, there is nothing unreasonable in the supposition that for some cause, not given, God withheld the flow of water to chastise them for their wickedness, as He did in other ways, and make them realize their dependence. As favoring this idea, when they were destitute the second time, and cried unto Moses in their distress, God told him to gather the people together and speak unto _the rock_. Not only was there a suitable rock present for the second river of water, but it seemed to be a particular rock. Hence designated "_the_ rock." Our conclusion is, therefore, that the two rocks were one; that it followed the Israelites during their entire journey to Canaan, supplying the people with the _fresh_ out-gushings of its crystal stream. That rock was typical of Christ, and the blessings of Christ are never stale or stagnant, as the water from a fountain in Horeb would have been, after winding its sluggish way through the parched desert of Arabia.
Whereupon Ahaziah sent a band of fifty chosen soldiers to arrest the prophet, who had retired to the top of a steep and rugged hill, probably Carmel. The captain of the troop approached, and commanded him in the name of the king to come down, addressing him as the man of God. "If I am a man of God," said Elijah, "let fire come down from heaven and consume thee and thy fifty." The fire came down and consumed them. Again the king sent another band of fifty with their captain, who met with the same fate. Again the king sent another band of fifty men, the captain of which came and fell on his knees before Elijah and besought him, saying, "O man of God! I pray thee let my life and the lives of these fifty thy servants be precious in thy sight." And the angel of the Lord said unto Elijah, "Go down with him; be not afraid of him." And he arose and went with the soldiers to the king, repeating to him the words he had sent before, that he should not recover, but should surely die.