While I didn't decline it (so I don't know exactly what the thought process was) I am going to assume it is as you suggest; we have more leniency towards opinions here out of necessity.
So, yes, the question is opinion based. But there are some formulaic opinions that are accepted as best practices that could be applied as answers.
You can also look through a lot of questions about "how do I save money" or "what should I do with my leftover budget" or "where to start investing" and see that this community does have a somewhat standard response.
Your comment was technically correct, but it amounted to "depends" and some advice to "ask a more specific question". What you might have missed is that for some of our community, knowing how to ask such a specific question is itself the problem that needs to be answered. For money.se, it is important to see the not the question as they wrote it, but what they probably meant. That is presumptuous to a degree, but if people knew what they meant on the more basic questions they could go somewhere else and find the answer. Our community has a several year history of welcoming basic understanding questions as well as the hardcore semi-pro day traders.
I liked the direction and tone of the two answers I see right now: they could be expanded a touch, but they are good. Both of the answers on the question prompted our poster to think deeper (and hopefully ask follow up questions) about setting goals and how one might achieve them. When I answer questions, I lay out a road map that works for beginners because, they have to start somewhere. Ideally, our community will be welcoming, new users will stay around and progress far past the 101 type questions. But we need to allow the 101's and help them on their way.