I do not agree, as excel is only one of the tools that can open such a document (.csv, tab-delimited...). As the requirement in most cases (really does not have to be this one) is to export data to a file and the contents of the file is ok when you see it through notepad, total commander or other tools -> from my point of view this is ok from the ABAP side.
But I understand there can be other points of view 
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