Is This Laziness Or Irresponsible? GAO: Army Reserve, Guard, don’t know how many soldiers are fit to fight.

SGT (Join to see)
It is not laziness or irresponsibility, it is bad systems planning and processes not designed to integrate because they were not designed for an operational Guard/Reserve program and need serious upgrades.
I can tell you that the Guard and Reserve has challenges when it comes to accurate reporting of all soldier statuses. This is not like active duty where you have daily accountability for soldiers. You meet once a month and 12-29 days per year for Annual Training. During your AT is when you have the most positive accountability and provide the most accurate reporting at the unit level.
There is very limited full-time staffing in a reserve or guard unit. For a company level unit you will have one full-time staff, at a BN maybe 2 or 3. All the reservist will do their best with 2 paid days out of the month and most senior NCO and Officers put in 'God and Country time' where you just work a couple nights a week and additional weekends for no pay because you are a professional and want to do a good job in the role you hold in the Reserve/Guard.
If a soldier has a serious accident, is incarcerated, commits suicide, gets divorced, etc. the Reserve Commander will not know until the event has been reported, which may or may not be the next monthly Battle Assembly. Let's assume all events are reported in the same month. When you roll up from company to BN, BDE, then geographic commands, add a funding overlay for what are the legitimate/funded structures, add all medical categories, dental, training, MOS Qual, Pay records, etc. These systems all have differences in the batch cycles and reporting periods.
Remember medical and dental for reservist are not covered, only the assessment of the soldier, so unless the soldier has medical insurance or joins the reserve system out of pocket then some medical conditions don't get fixed until mobilization.
You also have soldiers mobilized and sent with a unit overseas, but they must also have the data for this same reservist in the unit they originated from. The active, guard and reserve systems don't interface transfer data among the systems.
As a reservist that has been responsible for this reporting and provided briefing to GO level on readiness, we spend many weeks pushing to get data input into the outdated systems from our down trace units. Much of the reporting depends on critical system interfaces and I have had to explain the differences between my numbers and the reported numbers and why.
I could do it to the number most of the time, but it took weeks worth of time and effort to ensure accurate and meaningful soldier readiness stats.

SGT (Join to see), I do not believe that the issue is as bad as it sounds from reading the article. All this means is that what units officially report is not what may be happening on the ground. I'm sure there are times that units DON'T know what is going on, but I'm sure that is the minority.
If you ask any platoon or first sergeant I know, he'll know exactly how many guys he has, and what's going on with them. However, soldiers do get injured outside drill, and for whatever reason choose not to report it. And let's say a soldier breaks his leg in April. He knows that he'll be healed up by September when the unit has its next PT test. He tells the unit, and gets exempted from unit PT and rucking till he heals without ever getting a profile. Saves on paperwork, and causes the GOA a headache.
Another scenario could be a high speed soldier wants to deploy with another unit. He goes, but stays slotted with his home unit, to keep that slot from getting backfilled, because company leadership wants him back. It's not like nobody knows where he is, or why he's not at drill, but I'm sure it would draw a flag from the GOA.
Another reason, but less noble, is that commanders need to keep their numbers up. If a soldier is AWOL, it's not like nobody knows that he's missing, or that they don't kick him out. However to show better readiness, I can see a commander keeping an AWOL troop on the books until his chapter is final.

Where you have a difference between Active and Reserve/Guard Components is Active Units are seeing each other everyday. They interact closely and when you break your arm, your command knows.

Often, in Reserve/Guard Units, the soldier isn't thinking about their Reserve/Guard Unit when they break their arm. They are worried about their full-time employment and their Unit gets put on the back burner.

In regards to Reserve/Guard Units, could the AGR do more to reach out to their Soldiers? Absolutely. But, at some point also, the individual soldier should assume some responsibility.