Do you think in this case my relatives lacked of courtesy towards the birthday woman?

Earlier today my mom, sister, me and other relatives attended the80`s birthday of my mom cousin. Other cousins of my mom also attended and otehr cousisn of the bday woman as well. Some of my direct relatives (like 2 direct aunts, and some first cousins did not go, my brotehr also did not go). In the case of my family from my side mom (liek the aunts and cousins), one aunt already confirmed weeks ago she was not going to attend, my brother also said days ago he was not going either, but at least they did confirm so they were not going to be taken into account for the food, But then impolite part came with the other relatives who did not go: one aunt, one cousin and this cousin husband, and daughter. Plus anotehr cousin with his kids and one of the kids girlfriend, also did not go (that makes 8 of my closest direct relatives) These relatives names were included in the sitting table charts of the ballroom so I assume they never confirmed they were not going cause their names were on that chart or until the alst minute they said to the party host maybe by phone or the day before they were not going, but im sure the food was already paid for those 8 of my relatives who never confirmed a yes or a no, that is becuase the confirmation due date was September 5th. In fact one of them who did not attend but was including in the sitting chart: my cousin with his kids and his son girlfriend , did say he was going today but running late, but at the end he never showed up. I was told that the daughter of this cousin even weeks ago bought a new dress to attend the party and look nice, well she never go as her father did not go like I said and he said he was going but running late. I guess since he was running late he decided not even to show up. The other relatives who did not attend and were included as part of the guests attending like I said never go.

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Do you believe these relatives were impolite not to attend cause they were taken into account cause if they knew they were not going they should had confirmed the confirmation date September 5th.

I dont know the logistics of how that party was organized regarding the food but Im sure that if a person confirmed they were going the host paid for their plates and since they never attend the plates had to be paid anyway.
Do you think in this case my relatives lacked of courtesy towards the birthday woman?
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