I'm not picking solely on the local parade, here. I know that most of the major cities have their St Patrick's Day parade on Sat, even when the actual day falls on the weekday or Sunday. Heaven forbid it fall on a Sunday and the Catholics have it interfere with Church.
I fully disagree with the reason for celebrating it on a Saturday being that kids can celebrate it. It is a drinking holiday. Go to any of the large celebrations and tell me how many kids you see celebrating.
I do understand that more people will show up if it is done on a weekend, typically, unless it is in an area like SoWal where the majority of people work in the service industry, with Saturday being one of the busiest days of the week.
Glad you green people had fun, but I'm wearing my green tomorrow.