Fair point. I'd say it's sensible for the candidate to assume that context added to any hypothetical is there to inform their answer. Why add the context if it's not meant to inform? At that point it becomes fluff at best and misleading at worst.
It would make no sense for an interviewer to provide meaningless context unless they were deliberately attempting to distract from the the question, or are otherwise simply incompetent/unfocused. I don't see how gas-lighting candidates would be a productive mode of interview, particularly given that each party only has the interview from which to judge each others' character. Even if the candidate were to successfully discern the gas-lighting, all it would do is prevent trust from being formed. At that point every interaction would be subject to question.
So with the assumption that gas-lighting is not the intent and that the hiring party is competent, the question is how is the context meant to inform the response?
Given that the interviewer is gauging the candidate's ability to perform a job, it is sensible to assume that realistic-sounding context applied to a question is meant to see how the candidate would perform in what the interviewer deems a "realistic" scenario.
If the scenario is unrealistic but meant to impart other information, then it should be obvious or stated as such, so that the candidate can attempt to parse to the correct information from the scenario to inform their response.
If the point is merely to motivate the candidate to answer the question by placing themselves in a narrative, I'd argue they should be motivated enough by the fact that they're in a job interview, without the need for unrealistic scenarios. If they aren't then they clearly aren't taking the position seriously or likely have other issues that would impact their job performance even if hired.
Take the hypothetical removed from context: "You have make a deployable to-do list app as quickly as possible, speed and basic functionality are the only priorities. What tools do you use?..." That format accomplishes the same goal of revealing the candidate's knowledge of what a quick/dirty workflow looks like. The followup questions mentioned "what problems to you anticipate when scaling the solution? How would you on-board coworkers? How would you shift from rapid development to ongoing maintenance? etc" would then flesh out the candidate's knowledge equally as well.