I had this happen to me and I thought it was because it was a potluck and with all the people they had supplied wine of their choice.
I think they saw your wine as a gift and didn't want to include it in the masses and special. My guess would be the people that brought wine they took their bottles as well not necessarily for them but for possibly a more intimate dinner to be enjoyed.
I don't know just a thought. Yes the wine served at holiday parties in large groups leave something to be desired but hosting and supplying enough food and wine if people don't bring anything is a ton of work and expense. If you are not a huge drinker the quality doesn't matter as the quantity. Never happened till after my divorce but it probably happens more often than you think.