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.

Generally speaking, holidays should be (and usually are) avoided when planning drill weekends. That being said, there are two important considerations that factor into this:

1. Availability of resources - Sometimes the resources are only available on a holiday. This can include ranges, equipment borrowed from another unit, etc. In that case, you may just have to suck it up and drive on.

2. Local prominence of said holiday - Different parts of the country celebrate different holidays, and if you're not in line with the majority in your area, you may find yourself drilling on a holiday. For example, a muslim may have to drill during Eid, simply because that one isn't celebrated by enough of the unit to be a factor in planning. Similarly, hunting is a very big deal here in Wyoming, so almost all of our units plan enough MUTA-5s and -6s to ensure they can skip drill entirely in October. For this state, the start of hunting season is one of the most important holidays there is.

Not so much a "holiday", but the Super Bowl. In my area, a lot of us are huge football fans and the Super Bowl is a holiday to us.
Low and behold, drill is ALWAYS on Super Sunday! Why? Especially if we live in AZ, where we have hosted 2 Super Bowls in recent years, why wouldn't you pick any other weekend? Not to mention, the soldiers just don't want to be there when they know a party is waiting for them at home, or when they are off.

I vowed that when I took command we would not have duty on holidays or events that people typically spend with family. To me there is no normally scheduled training event that is so important as to trump family time. Any excuse about range availability boils down to poor planning. I refuse to make that excuse to my troops and have held up to it. I can't control what's above me but I've made my opinion known even if it risked making me sound like I wasn't being a good follower but I became a leader in order to change culture that needs people who stand up for the troops.

Working a holiday is just a part of life in general. If you are working a holiday, participating in quality training for the preparation of a deployment or something then drive on. If you plan a BA and sit around the R/C then shame on the Commander and Staff for being lazy and not thinking about the soldiers.

In Minnesota, the recurring problem is November. Typically we need to schedule SRP in order to administer flu shots. But Deer Hunting Opener is on the weekend typically scheduled for Nov BA. Not a lot of room to maneuver, since Veteran's Day and Thanksgiving occupy two of the other weekends.

SO chronically we are left with reduced attendance on a BA we are attempting to get 100% on Flu shots prior to the 1 DEC deadline.
It is a recurring leadership conundrum, one easily defeated by putting NOV BA in the last weekend in OCT - also a win because the weather is better for a make up APFT.
But people are fixated on traditional scheduling, so we do the same thing year after year.
Meh.

I command an Army band. We work on many national holidays. A former Chief, Army Music once said (and I paraphrase) "if you're an Army band and you're not working on Memorial Day, the Fourth of July or Veterans' Day you're wrong".

I think we should always plan ahead, Holiday is the time to relax with family.