Am I wrong shitty grandparents?

So long post sorry in advance

So this is about my my in-laws. We have been together 7 years and they have never really been involved in our kids life's. When we got pregnant with our first it was a horrible outcome do to he had a birth defect and we lost him after birth they never came to visit in the hospital and didn't even come to his funeral.or help out with paying for it. They don't go out to even visit him in the grave yard. They did once to decorate him because we didn't have the money and they said yes and put 3 $ of stuff on him they tossed eggs to the ground and an angel and that was all that was the only time they went out there. Fast-forward we get pregnant again a year later nothing didn't come visit in the hospital (healthy baby) they didn't meet him till he was almost a year old because they didn't want to and we went to a McDonald's and seen them they got him clothes that where left over from his cousins and an old night light and a new set of reaving blankets from Walmart. Then they didn't see him for over a year because they didn't want to no birthdays no nothing. Finally we get a good vehicle that can travel and we started seeing them more because we want to them to be in his life back in 2020 they start living at a hotel about 15 minutes away for that year then they moved about 40 minutes away and we started driving there 3-4 times a week just so they could be in his life he is now 3 at this time I get pregnant again and tell them they seem excited and are telling me what I will name the baby and so on even calling him a girl knowing he is a boy. I am about 6 months or so pregnant around Christmas and we go down there for them to spend 5$ on. My son and over 20 on the other kids he got two toys as the rest got 5+ and he didn't even get to come home with one because they gave it to one of the other kids because he liked it. Oh and might I also add on my son's 3rd birthday I was going to pay for a party for him with them and they said they would cover it promised him cake ice cream gifts decorations every thing just for us to be a hour late do to car trouble and they new this when we got there there was nothing no cake no ice cream no gifts no decorations they made a thing of brownies and they ate them before we even got there. Fast forward I have baby number 3 no call no show again. We took baby to meet them then they moved same distance different direction. Go visit them for Christmas just for my 4 year old now to get an open train set and a small unopened 5$ one from dollar general (they have a habit of getting his gifts out of the trash they gave him a torn up transformer for his 3nd birthday when they missed it and we started going down there as a late gift) and the other kids got 40$ toys one was that baby Yoda toy in the floty thing and the other was a babydoll set that came with a baby a stroller and stuff I know this because they left the boxes in the room we were in ( they live in a hotel again) and the other kids had to stay in his dad's room as we had to stay in my guys grandma's room. The kids got to go over there to play with their toys and we never got to even see the other kids. Idk what they got the 3rd kid

And there is so much more I know it's not about the money I was raised with pretty much nothing so I understand not having much. But to treat his sisters kids and cousins kids better he is starting to see it and I don't know how to explain it to him 😮‍💨 they have money so it's not an excuse 3 of them get like 2000 a month on ssi plus one works an they work for the hotel they live at and get paid for that to under the table so it's not a money issue I was that kid no one ever bought for my cousins always got more and I got barley anything if anything at all from other people my parents always made sure my brother and I got stuff and I do that with my kids and my parents are super involved with them so they know the difference in the way the are treated

Am I wrong for being sick of it when the other kids show up and we were there my son literally got thrown to the side like he was nothing. And he asks why they treat him the way they do and I don't know what to tell him.