I'm not sure it's really unreasonable to request a child not to be bought to Dr visits. Would anyone really want there child around unnecessary germs? MIl and FIL are in their early 50's not elderly INMHO. And yes there are other issues but ive moved passed them so that DD can have a relationship with her grandparents. Now i feel like i was wrong for doing that.
Like i said DD already goes full time to daycare she spent 1 day a week with IL's.
I don't think it is unreasonable EVER, that if someone is watching your child that you request that they not be taken certain places except in an emergency. Now if someone was watching your child full time, that would be something they would have to consider prior to agreeing to watch your child. I don't have a problem with certain family members watching my kids, but I'm no dummy and do have a limitation that I expect to be honored when they do watch them.
No--you cannot take my younger kids swimming. For a certain relative, no--you will never ever be allowed to drive any of my children anywhere. For another--she wouldn't dream of agreeing to watch my child if she has a doctor visit because those can take hours. I drag my kids to the doctor with me out of necessity--but it isn't a picnic.
And I don't think it is out of the question that when they have an unsafe arrangement that injures your child, that you request that the unsafe arrangement be eliminated.
My 2nd oldest sustained second degree burns at my mom's house when she was younger than your daughter. Her screams of agony and pain, I still remember. Her looking at her toes and pausing in her crying trying to figure out why they were hurting so bad still breaks my heart. Begging for drugs for her because she was in so much pain...and we typically try to "tough" things out as much as possible for boo boos.
My mom's water was hot--she knew it was hot, I knew it was hot. I made casual mention, but not wanting to tell her how things should be in her house, I never directly said anything.
That day, after our ER visit was over and my baby was drugged and napping, we opted to not return to her house for a few hours as we had other plans anyway. So we kept those plans. The ER instructed us on safe water temperature and one of the first things I mentioned to her when we called or went home (can't recall when I mentioned...) was about that temperature and I politely requested (although it was really a demand) that it be adjusted. They did--and they did not argue with me about it.
Now--it is purely at their discretion on if they will honor a safety request, but it is completely at my discretion if we would visit. (We lived out of town, so visits were overnights and even if they were day visits, the potential threat of a burn would still be present.) I didn't threaten, but I did request for the safety of my children. The consequence for not complying would have been not visiting their home.
You don't have to feel guilty or be bullied into believing that what you are doing is wrong.
No--we cannot tell people how to live or run their homes, but we have every right to grant or deny permission to visitation if that means our child is unsafe.
Keep up playing nice and don't regret it so you can keep the peace in the end. 
