My misunderstanding of the extent of Canadian polygamy law aside....
I can't see how enforced monogamy is defined as anything except forcing women to select a partner and to limit that to 1 man apiece. Especially, when the goal is to make sure that we don't end up with angry single men.
There is no concern about angry single women unable to find mates and the cost to society that they might create. There's also no emphasis on men only having 1 partner, not cheating, etc. I find that an interesting lack of emphasis.
The "reason" to enforce monogamy is to give some men something that they might not otherwise earn on their own but the restrictions are all stated in terms of limiting female action, not male. It's not surprising that some people might start wondering about unspoken intent.