Maybe it's just me, but I had a harder time with the first passage than the last two.

Hi there, I'm interested in joining. Is there a link available or should I look for a DM?

Think about it more as a matter of degree. If I am a good driver, that means I can drive a car. If I can't drive a car, then it entails that I am not a good driver. If I said something like, I won a Formula 1 grand prix, therefore I am a good driver, that would be more akin to a sufficient assumption, because it would correctly entail that I am an excellent driver, but it is not necessary to be considered by most people to be a good driver.