I may partly agree with you, in that the not constructive close reason was confusing and we don't use it anymore. I'm sorry it ever did exist--or, really, mainly just that it was called that. It's not one of the close reasons that can be selected today. However, that question shouldn't be reopened. We would still close it if it were asked today, we would just be able to select a close reason that makes more sense. I think three of our current close reasons apply:
Too broad. There's really no limit to how many distinct answers could be posted. And if a single answer tried to address a large chunk of the question, it would be enormous, at least if it tried to explain its judgments. In the case of this particular sort of question, requesting a big list of answers, this overlaps with "primarily opinion-based" too (see below).
Unclear. What does "must have" mean? Does it mean "greatly beneficial"? Does it mean "really cool and you will tell your friends"? Does it mean "your system isn't worth using without it"? Does it mean "good to know about"? Does it mean "more than X% of users will like it?"
Primarily opinion based. There was hardly any standard by which to judge the appropriateness of the answers besides personal opinion. The question was not an explicit call for discussion, and to a limited extent facts and experience were a factor in determining what people would post and how people would vote on them. But mostly arbitrary opinions--that is, personal preference--was the major factor governing what answers would exist and how well they would be received. The top-voted answer recommended VLC. Why was that something people "must have"? Did those votes really reflect that VLC was the most important program to install? Did they reflect that it was important at all? Or did they just reflect that VLC is generally well-liked?
The question was not just subjective in the sense of not having any provably best answer, which is true of many perfectly good questions. It fell afoul of the problem that just about every answer that might plausibly be posted was equally valid. This part of the existing closure explanation applied fully:
We expect answers to be supported by facts, references, or expertise
The question itself contains some hints that it was never actually a good fit for our site:
- If you look at what most of the text in the question is doing, it is mostly giving advice about the special and different way one has to use the site to answer it appropriately.
- It emphasizes searching--not reading, or skimming, or perusing, but searching--the existing answers before posting another. That is, it was expected that most people would not actually consider what the existing answers said before writing their own. It was expected that there would be so many answers that most people who came to the question would not look at all of them.
This is to say that the question was in effect a poll asking people what their favorite software was, and not something that could practically answer a new Ubuntu user's question about what additional software they would be well advised to install on a fresh Ubuntu system.
As mentioned in the comments, the question was really a duplicate of What are the most useful programs installed after setup of a vanilla Ubuntu? which was subsequently deleted by a moderator. (If this question had remained open for longer, or if we were to reopen it now, more effort would go into and then it would still likely be closed eventually and then deleted, too, either by a moderator or from community members' delete votes.)
There's an argument to be made that the other, original, deleted question should not have been deleted by a moderator but should instead have been deleted through the gradual accumulation of community members' delete votes, or even that it should have been preserved with a historical lock. But the question you've asked about was just a rehash of it, is unlikely to warrant special treatment, will likely be deleted eventually, and would likely have been deleted a while ago if it had captured more attention. After all, it says:
Inspired by this question. I think the question was very useful for Windows users.
That question, on Super User, has since been deleted.