SE sites have certain standards of quality and certain scope limitations. Check the FAQ, specifically sections about what can be asked, and what should be avoided. When the user makes cryptic and vague statements — they run the risk of being downvoted. When a user makes statements that are unsourced, or outright plagiarizes — they run the risk of being downvoted. When the user is following a mantra such as exampled in the quote below — they run the risk of being downvoted:
Точность формулировок, терминология, библиография и прочие мелочи = чужая мне печаль.
One does not have to be a guru in any particular area of knowledge, to make an informed and responsible decision about the quality of any given source. That is a fundamental research skill that is taught at any university, alongside of other fundamental skills, such as proper methods of gathering, evaluating, and analysing data in the laboratory. Given one particular user’s “shameless acknowledgement of ignorance” in these matters, they are in no position to complain.
I, for one, downvoted only single one (1) of said user’s myriad of questions and answers, ergo there are at least five people “who systematically downvotes” poor content. As the saying goes: if everyone around you is an expletive, maybe it is time to look in the mirror.