This isn't really an answer to your question but more the lines of another question.
Why do people take cruises if they don't want to get dressed up for dinner? Stay home or take a land based vacation or cruise on another line which is more casual, i.e. NCL.
Why do people always have to make excuses for not dressing up or trying to go to the dining room inappropriately dressed.
That's the one thing we love about cruising is dressing up.
Most people on Celebrity cruises DO adhere to the suggested dress code.