The macro recorder does not record formatting associated with the replace
tool so your macro finds nothing and replaces it with nothing. You must add
the required font formatting manually eg

Sub Macro1()
Dim sView As Boolean
sView = ActiveWindow.View.ShowHiddenText
   ActiveWindow.View.ShowHiddenText = True
   Selection.Find.ClearFormatting
   Selection.Find.Replacement.ClearFormatting
   With Selection.Find
       .Text = ""
'********************
       .Font.Hidden = True
'********************
       .Replacement.Text = ""
       .Forward = True
       .Wrap = wdFindContinue
       .Format = True
       .MatchCase = False
       .MatchWholeWord = False
       .MatchWildcards = False
       .MatchSoundsLike = False
       .MatchAllWordForms = False
   End With
   Selection.Find.Execute Replace:=wdReplaceAll
ActiveWindow.View.ShowHiddenText = sView
End Sub

The macro also ensures that the hidden text is displayed before deleting it
regardless of whether it was displayed previously, then resets the display
to its previous state viz-a-viz hidden text.
http://www.gmayor.com/installing_macro.htm