Paula Marantz Cohen defends the use of “like”:
“Like” is a comfort word in some respects. It gives those who are tentative or unsure a chance to sidle into a point. It is a marker for uncertainty: “I, like, think I’m going to, like, go to medical school, only, like, I’m not really sure.” That’s qualification with a vengeance, but, then, the subject—whether to spend years in medical school followed by a career ministering to the sick—warrants such uncertainty.
“Like” is also a way to diminish or cushion the force of an idea or to acknowledge an approximation of meaning. One’s first inclination is to be annoyed that the speaker has not found a more precise word. But the right word may not exist, and the approximate word, softened or qualified by “like,” may be more precise. I used the word a while back in my course on Paradise Lost: “The thing you have to realize with Milton is that even if you don’t, like, ‘believe,’ there is a wealth of profound observation about human relationships in the poem.” Here, “like” gives the listener a bit of latitude in how to understand “believe.” It also opens up the idea of belief in a way I felt was helpful. For some, it might seem I was being sarcastic, for others that I was simply acknowledging their probable uncertainty about their own belief or the difficulty of pinning down what belief actually consists of.