Why do we have to be so political in friendship?

We have (or used to have now) these two other families where all of our kids are in the same age and we don't live that far from each other. We used to organise playdate and our kids love playing with each other. We thought we can rely on them and they can rely on us as well.

But recently, whenever we try to organise something, they always not available and sometime they don't even reply to our messages after few days later.

Then one day we found out through Instagram that they actually went on a trip together without inviting us. They planned playdate for the kids also without inviting our kid. And now, they are ghosting us and never talk to us anymore.

We are so confused and very disappointed...why did they treat us like that? We never had any conflict between each other. The only reason I can think of that, one of the mom's friend was actually close to my ex...but it was 10 years ago that I was with my ex. And maybe she does not want to be seen that she is now close with us???

This may just be a rant..but sigh..why do we have to be political in friendship? Sick of this situation...we felt so betrayed..

We know we can always find other friends that can appreciate us. But it is never easy to lose some friends who already close to you and they now left you just because of something that has happened in the past.