Your code depends on all the text being red and bold which may not be true but also Replace > Whole words setting will cause problems because of the way spaces are treated (not as words)
This code does not use replace and should unbold spaces and set to black (you can easily change the black to whatever) It may take a little while but a lot faster than manually!! Make sure you test on a copy
Code:
Sub killRed()
Dim otr As TextRange
Dim oshp As Shape
Dim L As Long
Dim C As Long
Dim osld As Slide
For Each osld In ActivePresentation.Slides
For Each oshp In osld.Shapes
If oshp.HasTextFrame Then
If oshp.TextFrame.HasText Then
For L = oshp.TextFrame.TextRange.Paragraphs.Count To 1 Step -1
Set otr = oshp.TextFrame.TextRange.Paragraphs(L)
For C = otr.Characters.Count To 1 Step -1
If Asc(otr.Characters(C)) = 32 Or Asc(otr.Characters(C)) = 13 Then
If otr.Characters(C).Font.Color = vbRed And otr.Characters(C).Font.Bold = True Then
'otr.Characters(C) = "@" optional
'delete this to change to @
'''''''''''''''''''
otr.Characters(C).Font.Bold = False
otr.Characters(C).Font.Color = vbBlack
''''''''''''''''''''
End If
End If
Next C
Next L
End If
End If
Next oshp
Next osld
End Sub