Hi Carolina--
You could write your own ACL function to delete all selected rows in a table, and then either re-alias it to the menu item or add a different menu item such as "delete multiple rows".
If that's more ambitious than you would like, there are a couple of workarounds that are less painful than deleting one row at a time:
1) Since you have only one column, you can select the rows you want to delete, select "Span cells" to convert them to one big row, and then delete as usual. Since it's now only one row, the regular Delete->Row operation works fine.
2) You can turn on table markup (View->Tables->Table Markup). This will show the markup for the table, allowing you to select the desired <row> elements and delete them in one go. I wouldn't recommend this for tables of any complexity, but since you only have one column this should be manageable in your use case.
Also, I think this would be a good product idea to submit to PTC. It sure seems like it should work the way you expected it to, and would save some hassles in working with tables.
--Clay