A little simpler, and a lot more general

Try this


Option Explicit

Sub HideRows()
    Dim rCell As Range, rData As Range
    Dim sUsername As String
    
    Set rData = Nothing
    On Error Resume Next
    Set rData = ActiveSheet.Columns(1).SpecialCells(xlCellTypeConstants, xlTextValues)
    On Error GoTo 0
    
    If rData Is Nothing Then Exit Sub
    
     sUsername = UCase(Environ("Username"))
    
    For Each rCell In rData.Cells
        rCell.EntireRow.Hidden = (UCase(rCell.Value) = sUsername)
    Next
End Sub