Why lot of questions are closed on the name of being 'primarily opinion-based' ?
All the answers I read here are primarily opinion based because the questions of this field are of that nature (otherwise we would not be struggling with the same issues since software engineering was born). If programming itself is an art -thus subjective, primarily opinion-based - how dare you claim that software engineering is maths?
"lot of questions are closed as 'primarily opinion-based'" - looking at the stats from the last 90 days, from 772 closed questions, only 50 were closed as 'primarily opinion-based'. This makes 6.48%, which I would not call "a lot of"
software engineering is neither 100% opinionated nor 100% math, it is mainly based on experience. It is a broad field where some topics are definitely very opinionated, and others can be backed up by scientific research and statistics. But IMHO the majority of topics relies on expertise of people working for decades in that field, and for several topics there exists some consensus among those experts. The close vote "primarily opinion-based", however, is often used for telling askers "there is no experts consensus on this, this question is quite unanswerable".
it is very debatable if programming should be seen as "an art". Most experts I know see it more as a "craft", and if I had to guess I would say less than 5% of programming looks like "art" to me, "95%" or more like "craft". But for all those comparisons you will find examples where they don't fit well.
So if you find a question which is closed as "too opinionated" where you think the close reason does not apply, feel free to ask a question here on meta about that specific example. That would be way more constructive than challenging a whole closing category by debatable arguments.