Don't take it personally.
It's annoying because it feels like a personal attack, but it isn't. It's the schools job to educate and also to (increasingly) be aware of situations at home that are impacting negatively on the child's progress - which is linked to their concentration.
Most children get a bit sleepy in the afternoon - body directing resources to digesting lunch, and a busy morning all contribute, which is why most schools will timetable numeracy and literacy for the morning and topic work for the afternoon. We also do DD's homework in the morning before school because she's just too tired in the evening.
I think good parents, who prioritise their children and have good routines, do feel 'got at' (me included and I'm a teacher too!) when this kind of thing happens.
I also think those same parents would be horrified and in disbelief at the situations some children do live in.
I often type out posts on threads giving (anonymous) detail about children and families I have encountered/worked with through teaching and working for SS. But then I delete them because I know that there are too many people on here that just, frankly, wouldn't believe it. And we're not talking of the level of startling abuse that makes the news, just low level but persistent thing. And often it manifests in children not getting enough sleep and being tired during the day.
Unfortunately, Ofsted don't accept that a child's homelife can impact on their progress and the school are still expected to show the same improvement. As a result sometimes teachers have to ask these questions.
It's annoying for all concerned!