I think what's being said here is that it's easy to pick up the ideas of visual design, not the actual skill (I hope). As a budding designer, Dribbble is definitely helpful in allowing you to see "the bar" and improve how you approach certain projects. However, it is most definitely NOT easy to "pick up [visual design] by cruising Dribbble."
Design is a solution to a problem. It doesn't matter what the medium is. Sometimes you see these solutions on Dribbble but more often than not what you see are examples of style. They are two separate things.
