If you just do stuff without reflecting on why it's necessary that's... odd. Two of these examples have actual reasons on why they're necessary, the third is because screenreaders are crap.
I'm not trying to be difficult, but how is it any different than matching what an HTML parser (such as a web browser) expects by making sure you close your tags?
Excellent example because web browsers will render most documents just fine if you don't close your tags. Because they care about being compatible with websites that aren't perfect, and they consider it their job to render all websites that exist. Instead screen readers expect you to change your website instead of working with what's already there.
