It seems to me that your answer is mostly a collection of comments. The format of this site is somewhat rigid.
First, there is a question-post that should present a question.
Then, there are answer-posts that should answer the question presented in the question post, and mostly only that.
Reflections and opinions on other answer-posts- or the question-post should be presented, if they are made at all, as comments to the respective post. The should not be presented as an answer-post. Each answer post should mainly try to answer the question presented in the question-post. It is alright to reference existing answer-posts to contextualize one own answer-post in the thread, or to include an aside.
But first and foremost an answer-post must be an actual answer, or at least an attempt at it, to the question presented in the question-post. (It cannot be merely a contribution to the subject in general as an "answer" in a thread of a discussion-board might be.)
If it does not do that it should be removed. This is what happened in this case.
Let me add an afterthought to this. There arguably are some exceptions to the principle above, a culture of those is more developed on sites where this is more relevant. Sometimes somebody might ask a question but in one way or the other one thinks that the person just is not asking the question they should be asking or solving the problem the should be solving.
In such case it can be helpful to answer via a "frame challenge" see
Does Stack Exchange allow for answers which question the validity or stance of the original question?
Another relevant concept is XY problem. See What is the XY problem?
However, these answer should only be given sparingly and when the context makes likely that this is helpful. (In cases of doubt one should solicit this context.)
For the current case, I just do not see this. Somebody doing such integrals is usually doing so because they have to do this as part of a course or alike, and moreover ultimately they usually also have to do so in a constrained environment. Answers of the type: "look it up" or "use a CAS" just are not relevant answers to the underlying problem.
To put this differently, the answer given, could be identically given to hundreds if not thousands of questions that ask how to do some integral or another. Variants of it could be given to tens of thousands of questions.
- "Q: How to compute the determinant of this 3x3 matrix? A: Plenty of software can do that."
- "Q: What are the eignenvalues of of this 3x3 matrix? A: Plenty of software can do that."
And so on. It usually just is not a helpful answer. It might be in select few cases, but if the context clearly suggests it is not, then such an answer should not be given. In cases of doubt, I would put the onus on the person that wants to give such an answer to check if this type of answer is relevant.