Many times I had the problem of alignment of the text when I had a bar chart with positive and negative values. Where the text was placed in the left and on the right side of the axis.
Something like this:
This is the problem of having one axis and Labels in the same place.
In order not have this alignment problem you can create a dual axis chart and then you can control the alignment as you want.
The Dual Axis can solve the problem
Now all the Labels are placed on the same side and this issue has been solved only by adding a secondary axis.
This video shows you how you can do a bar chart in Tableau with the label alignment.
..and if you want you can download the workbook from my Tableau Public Profile.