replyTitle: "who decided it would be a good idea to teach beginning web developers that <B> is the “Bring Attention To” tag and <I> is the “Idiomatic Text” tag"
Going forward, the [CSS Speech Module](https://www.w3.org/TR/css3-speech/) seems like a better place for auditory tonal indicators. The CSS we've already had for years should be a better place for visual presentation.
This leaves only a minuscule semantic difference between `<i>` and `<em>`, or `<b>` and `<strong>`, as outlined in the HTML Living Standard. I don't think that difference warrants extra elements in the HTML standard: the extra elements likely create more confusion than actual benefit. Over the past decade, I'm unaware of any user-agents treating them differently enough, in a way that aligns with author intent, to matter.
I personally just avoid `<i>` and `<b>` when authoring. The complexity is more trouble than it's worth.