I also have noticed this trend.

Short response: there is no quality control on the actions of MathSE reviewers, who are often affected emotionally because MathSE is inundated with low quality postings, many of which refer to very elementary math.

Sometimes, when there is a low quality posting that is of somewhat advanced math, the MathSE reviewer's emotional reaction will (quite naturally) not be so intensely negative.

My best advice is to ignore the fact that MathSE reviewers are not robots.

From your perspective, your goal should be to get your question answered, regardless of whether it involves a very elementary math problem. So, from your perspective, I suggest that you look for defensive measures, such as those offered in the next paragraph.

For what it's worth, virtually every MathSE posted question that I have seen, that followed this article on MathSE protocol has been upvoted rather than downvoted. I am not necessarily advocating this protocol. Instead, I am merely stating a fact: if you scrupulously follow the linked article, skipping/omitting nothing, you virtually guarantee a positive response.

Addendum added to respond to comments.

I also have noticed this trend.

Short response: there is no quality control on the actions of MathSE reviewers, who are often affected emotionally because MathSE is inundated with low quality postings, many of which refer to very elementary math.

Sometimes, when there is a low quality posting that is of somewhat advanced math, the MathSE reviewer's emotional reaction will (quite naturally) not be so intensely negative.

My best advice is to ignore the fact that MathSE reviewers are not robots.

From your perspective, your goal should be to get your question answered, regardless of whether it involves a very elementary math problem. So, from your perspective, I suggest that you look for defensive measures, such as those offered in the next paragraph.

For what it's worth, virtually every MathSE posted question that I have seen, that followed this article on MathSE protocol has been upvoted rather than downvoted. I am not necessarily advocating this protocol. Instead, I am merely stating a fact: if you scrupulously follow the linked article, skipping/omitting nothing, you virtually guarantee a positive response.

$\underline{\text{Addendum}}$

It seems as if the portion of my answer before the Addendum may have been interpreted (perhaps reasonably) in a manner different from my intent. The thrust of my answer was not that MathSE reviewers are too critical of low quality questions involving elementary math, or that the reviewers' actions in this situation are (irrationally) emotionally based.

Instead, the point of this answer was to allege that sometimes, MathSE reviewers are not critical enough of low quality questions that do not involve elementary math. The second point of my answer was to give a speculative psychological explanation of why MathSE reviewers might behave in this manner.

Also, there is the third point, which I will again emphasize. From the viewpoint of the original poster of this meta-question, who (I surmise) wants to get their posted questions answered, the focus should be on what defensive measures to take (i.e. pick your battles).