A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data
I believe that's by design and you can't change that. Histogram are meant to show the bucket [from value, up to but not including value]. If your values are whole numbers between 1 and 10 I'd suggest you create a regular clustered column chart with a small gap width and adjustable axis labels. Use COUNTIF to count the number of occurrences of each number. If you have decimal numbers between 1 and 10.9999 you could round them down first (i.e. take their integer values) in a helper column and then use COUNTIF on those.