I just experienced the same problem and have made a simple work-around. If you have your labels for the Y-axis in for example A3:A13 you need to create column B where you input =A3&REPT(" ",MAX(LEN($A$3:$A$13))-LEN(A3)) in B3 and copy downwards. This will add blank spaces so that all labels have exactly the same length as the longest label in the range A3:A13. Use column B for your chart instead of column A.
And now, here comes the trick, go to the chart and mark the Y-axis and select a monospaced font, e.g. Courier, Lucida Console, etc. This will make it look like it is left justified, I hope this can help!
I noted that my solution works only for one row labels, for multiple row labels the auto wrapping will make a mess...