Battle Assembly on a Holiday?

Poor planning - if your operations / training puts it on the schedule and doesn't vet it during YTB there's no excuse for it. Period.
I've been a part of YTB at company and BN level and we go as far as to avoid times that are big local events (race day, college football, etc.) Partly because you want to let your soldiers and their families spend that time together, and partly to avoid traveling during busy weekends - for safety if nothing else.

As a former National Guard company commander my focus was on retention...you work very very hard to recruit new members but it is imperative that you retain those that you already have and avoid the revolving door syndrome... which breaks up cohesiveness, especially in a reserve component outfit...so my my thoughts are NO Keep the spouse and kids happy about the SM being in the your unit and you will retain far more personnel through good planning. AT's can be tough to avoid sometimes but holidays on normal drills are avoidable for the most part as planners.

I've drilled on mother's and father's day and once on a memorial day, I absolutely agree that it is poor planning on the staff/commander. If holidays/remembrances/super bowl can be avoided I believe they should be. However, we signed a contract and committed to do our time and no where in the contract were holidays excluded. Sometimes we just have to suck it up and do our duty.