But a lot of these posters had kids 6 or 7 years old. My daughter is in 6th grade so I do understand what you and the others are coming from. But really is there that much homework at that age? Is putting down the one extra step that big an effort? Another comment which wasn't by you is laughing with your kid about the teachers instructions. They may be funny but I think that's a bad habit to get in.
Homework varies. Most nights it isn't too bad, maybe 4-5 worksheet pages. The issue really was trying to get him to show work in the prescribed way, when he was more than able to do math problems like 24 plus 39 in his head. So, in his mind (and mine), it was busy work and the methods they were trying to teach (i.e., filling in grids or arrays) were a true step backwards. The extra steps may not individually have seemed like a lot of effort, but yes, it does take time to fill in that many dots in an array (especially for a kid who dislikes writing). Time that could go to much higher level purposes.
That said, yes, he understands that if there is any question of the teacher needing to check his thinking, it makes sense to write down the steps. Now that the school has him in fourth grade math, we're not seeing the same level of frustration with this topic as we were when I first posted, fortunately.
I believe we started pre-algebra in 8th grade when I was in school, perhaps earlier.