Speed limits are chosen to facility smooth traffic flow.
No, they’re not. Speed limits are intended to dumb down the driving environment so that the “lowest-common-denominator troglodytes” can cope. Even so, many still can’t. We learn about them in accident reports in the news. Much of the problem arises from the negligible value placed on driving well for its own sake.
Too many cars traveling too fast results in increased congestion
You mean the way to go faster is to slow down? Try selling that idea to NASCAR drivers in the Daytona 500.
If you prefer not to drive fast, that’s fine. But please don’t invent spurious reasons why no one else should.