There is no way to disable alerts displaying on a chart when looking at a single chart. The above image shows what an average chart looks like when looking at a single metric. It is very difficult to make out the line with even a single line, and almost impossible when there are multiple lines. In this example too, none of the alerts affect this metric at all, so they have no utility.
I propose that there is a way to disable alerts at the chart level, or better yet, have a configurable option per user to have alerts disabled for charts and dashboards.