Despite polygyny being an honorable form of marriage, many disagree with it; saying that it contributes to dysfunctional households, it's only beneficial to the husband, all of the like.
And some, oddly enough, prefer for a husband or wife to commit an immoral act - such as cheating - rather than get involved with polygyny. But they aren't anti-monogamy.
In this video, Coaches Nyla, Nazir, and Fatimah deep dive into how being "anti-polygyny" makes one, by default, "anti-marriage".
Nyla, Nazir, & Fatimah