No car that is roadworthy is unsafe, the unsafe bit is the person behind the wheel. Another thing is, to the OP, the driver who coasted up to the roundabout was unsafe, not the car. You should already be in the right gear when coming up to any corner in a manual. Some autos I find unsafe to be honest, the thing is with an Auto it decides what gear it wants to be in, but the auto can't see the cars coming at a roundabout so if it decides it wants to be in second and you want to come out of the roundabout fast, second is wrong.
My 7 series for example, Jags with the 6 speed auto suffer the same issue, unless you come to a complete stop it stays in second gear, now if you accelerate hard without stopping, it starts to drive in second at full power but it can't do it, so it thinks right you're asking for full power here, now I need to change into first, that second it takes to do that, a manual car would've been and gone.
In a manual any good driver should always be in the right gear and ready to go. Autos just cannot do that like you can in a manual, unless you change it manually which defeats the point of an auto. I find autos much nicer to drive and I wouldn't really want another manual car, unless I get something stupidly fast again. But in my opinion manuals are safer if you're any sort of half decent driver.