The OP knowing better than to post a node lacking certain content such as what has been tried is not mutually exclusive of the question being asked being a useful question. The node is incomplete perhaps. It may be rude in the author's omissions, but it is not rude in the content it includes. It defames nobody, incites none to violence, advertises no product unsolicited, contains no profanity, and in fact blames no other member of the site for answering or not answering in any particular fashion. The question can quite easily be answered for posterity even if we have reason to believe answering briefly and clearly with exact information will do the original poster little or no good. I can't say I'd give it a vote to the good knowing the background, but considering it apart from the poster's background I certainly wouldn't accuse people of necessarily supporting the textual content of it thoughtlessly.
The way you separate the poster's habits from the content of the particular node is just that. Consider the node's content without considering who wrote it. Not everyone is as familiar with the OP as we. They may find something redeeming in the question without knowledge of who asked it or without consideration of that person's past behavior. Don't blame them for that. They are just examining the ideas and not who presents them. Some consider that an ideal. At least one member here has been known to have a similar plea in a signature line used to sign posts.
Your idea of "highly redundant and wasteful" and mine must meet different magnitudes to qualify as "highly". The poster in question has asked four root-node questions in the past year or so. This person has asked other questions about Excel in the past, but they do not appear to me at this time to be the same question about it. The only thing highly wasteful is that habit of not providing more background research and the false laziness of it. The volume of questions and the overlaps of their content don't seem to be "highly" anything. Ignoring the question for spite and having many people later stumble across it unanswered in searches seems much more wasteful to me.
Don't think that by defending a node I'm condoning a pattern of behavior. I'm not. I think the node in question could have been much better and that the poster should know by now how to make it better. I'm just saying there are perfectly valid reasons it's not universally voted down and maybe even deserves a little noise in the signal toward the positive based on the merits of the text itself.
If we only defend the most popular utterances by the most popular of speakers then we do not strengthen our discourse. The popular need little defense. It is by matters of degree and by allowing for faults in good work or merit in poor works that we improve ideas over time. Tearing down the faults of the good for their being faults and building up the merits of the faulty for their being merits is what sets the truest examples. Accepting everything or rejecting everything from a source based simply on preference for or against that source is a sort of self-imposed ignorance. For those who call self-imposed ignorance wasteful, it is sad that they would dismiss a valid question only because the asker will make poor use of the answer. It only becomes two cases of waste where there was one.