Goodness you're aggressive, mummytime, there's no problem with NanaNina and DILs that I can see. Perhaps it's just different perspectives.
In my world, there are some things a child must have autonomy over, ie. touching (outside medical and safety intervention) and kissing. They can have an opinion about everything else under the sun but they don't get to decide where they will be and what they will do - at all times. An example of that would be the thread about the meal out for an engagement. Most posters said the children must get on with it (I agree) but some said that the children shouldn't have to if they don't want to... I think that's very weak and all it leads to is dissension in a family whereby other family members are less disposed to making concessions for children who 'can't be bothered, because their parents can't.
The language used about MILs here is really quite inflammatory and, if used in the real world (which I don't believe as so many have such a problem with even polite confrontation), it's needlessly rude and the same point can be made - to the same end - with a much kinder tone.
Suggesting that you will "Have a word with" MIL can either be something like, "Oi, MIL, daughter doesn't want to see you and I'm not going to force her to love you if she doesn't and you're not to make her say it...." all the way through to "MIL, she does love you, you know that really, she's just saying that she wants to stay at home today/tonight. I know that she loves doing baking/drawing/painting/reading with you so how about I bring her on x-day for you to do that? Or maybe come and visit us and have lunch/dinner?"
There are ways of treating family members. Some are better than others. I'm not saying that there aren't toxic MILs out there but would say that there are probably as many toxic DILs to that number.
On the 'emotional manipulating' point I'll just say to you that as a teen, I used to accuse my mum of manipulating me (into desired behaviour) - and she was right. I expect I upset her with that comment though and I expect your child will upset you and make you question your parenting at some point.
We all parent differently; some parents absolutely cock it up for their poor children when parenting is hard enough as it is anyway without the aggro. I want my children to be loved within the family, not ignored because of my peculiar antics so I try to keep them to battles I really do need to win. We're all different.