Using that Export function exports the entire table - all columns and all rows... I believe what @Jenny Franklin wants is the ability to filter a column in the Table step, and then only export those lines. I don't believe this functionality exists yet. We requested a RFE for this a while back and encourage you to do the same to help expedite it.
If you're pipeline is simple (like the one above), just temporarily add the column filter you want to the Filter step, then export and revert the change. But if you're pipeline is complex (e.g. the Filter step is early on and there are multiple steps afterwards), there's no way around this that I'm aware of - have to export the entire table then filter in Excel.