What is a good way to respond or comment to a boomerang answer? [duplicate]

Question

What is a good way to respond to a boomerang answer, an answer that basically responds with "You don't want to do that, do this other thing"? Maybe I do want to use my cat as a mop for my kitchen floor (Stack Overflow Podcast).

I asked a question, a person answered a bit of it, and then they summarized it with "You only need to trust the service doing the access".

The user put a bit of good work into the answer that I think is useful. But I would like to point out to them that it is not an answer to my question, without losing their work.

Answer 1

Just respond honestly. Thank the user for their effort, and point out to them that you can't actually use their answer for whatever reason. You could leave a comment reading something like this:

Thanks, this is a helpful answer, and under different constraints, this solution would solve the problem. However, due to ... blah blah ... I am unable to trust the service doing the access, so I can't use your solution.

If you think the answer is useful, you can upvote it. Obviously, you wouldn't accept it, since it doesn't solve your problem.

Of course, you should make sure that the question is clear about the constraints you have. It can vary across sites whether you're obliged to explain why you have those constraints, but if you can do so, that's definitely helpful.