I have a lot of the same feelings as @jorlauski—I'm not worried about a downvote as much as I don't want to discourage a writer who is still learning. On the whole, I prefer only to give constructive criticism where it explicitly asked for, or where I know the author well enough to know they are open to it. If I really can't get through a piece because it is badly written, I seek another piece to read. Does that leave me clicking away from/not engaging with people who might benefit from it? Perhaps. On the other hand, we all have different levels of education and want different things from this platform. Those seeking to become better writers will engage in communities that will encourage that, and those who aren't interested will do their thing too.

On this issue, I'm pretty live-and-let-live.