Grandparents babysit but are disinterested?

Sorry if this is long but I need a sanity check...

My mom and my MIL alternate watching my two girls ( 2.5 and 6mo) at their own homes. I drop them off in the morning, pick them up, pack food, etc. Before I had the second baby they each watched her two days a week.

When I was on maternity leave they would each come to my house one day a week to “help” with the older one but they both pretty much backed off most help. They never offered to help with the new baby and each time they came over it was me catering to them like they were company. My mom in particular would take off many weeks and go on various vacations and not really ever ask about the kids. My dad made comments to me saying “well you need to learn how to raise 2 kids” and my mom has made other similar comments. (I’m an only child FYI) when I would ask if mom planned on coming over during the week at all.

When I went back to work after the second I went back part time and now they alternate watch the girls 1day/ 2 days each week. My mom made it very clear that when I pick them up from work I am to go straight to her house and get them and not to make any stops along the way. ( I work 8 hr days and both kids take at least 2-4 hrs of naps through the day).

They only see them on the days they watch them and they make me feel terrible for it but then they say how much they love watching them. I’m so confused. I only have them watch my kids because to me it was important for them to have a special relationship with their grandparents.

Am I crazy for feeling like they are disinterested in their granddaughters? I know they watch them during the week but I don’t really feel like I have support..