Tbh I can sort of relate to the OP - but I think it's more to do with family dynamics, and not being quite as comfortable giving instructions and saying exactly what you want - as they're not your own parents.
It used to drive me nuts after PILs had been babysitting to find baby still awake, being bounced on knees at 10pm, the moses basket in the middle of the lounge instead of staying upstairs as requested (because we were trying to sleep train). Oh and the stinking nappies that were mysteriously full to overflowing even though "Oh, I did change her...[but I thought I'd leave that one for when you got back]" Other times Dd1 being dressed in layers of woolly clothes when everyone else was in t-shirts and shorts, stuffed with sugary biscuits at every opportunity...
After a while it just became obvious that some of it was down to my insecurities as a first time parent (is baby your first?) - desperate to 'prove' I was doing a great job, and seeing every difference in approach as an affront to my ability to parent. They were doting grandparents who had been through it twice (albeit decades ago) and much more relaxed about various details. Took it all less seriously - but it felt like they were taking me less seriously, as a mother. Also it bugged me that every time they babysat, it was like the first time - i.e. I had to explain everything again, like they'd never done it before - but actually it was just that babies do change even in the space of a few weeks, so things you take for granted, they really aren't that familiar with.
But...that was with the first baby, by the time our second came along - I was so much more relaxed - and grateful! Dispensed with neurotic, control-freakery instructions and took the attitude of 'when you're in charge, you do it your way' and it was much better all round.
Neither dcs have been harmed - they love their grands.
So YANBU for being a bit pissed off, but YABU to expect them to do everything the same way, and make the same choices you would.
YABVU to think men don't change nappies - what decade are you in lol. Err...no! That is not the norm.