You may find snooty people on any cruise line.
We have done 5 OCEANIA cruises and yes have met 1-2 people that were snooty but for the most part people are friendly.
I have never sailed on Celeb so cannot compare but I am sure you will enjoy O
We were booked on that cruise.... the Regatta will be going into drydock following the crossing so we could not continue on to the Med so we cancelled.
We will do the MED in May instead
enjoy the cruise