E-mail was always asynchronous communication tool.
For people who like to see waving three dots in iPhone chat, e-mailing makes them anxious. So I understand that apology is quite normal.
It is a sort of generational difference, imho.
I took a day off texting to sleep and recover from an injury, and the woman I was seeing (in her 30s) threatened to delete our chat because she assume I was mad and ignoring her.
She's part of a certain digital generation, and expectations change.
A younger PM I'm working with right now emailed me twice in a few hours because I didn't immediately sign into their management platform after our 4pm meeting. Granted, that's her job, but the project doesn't officially start for a few more months.
> generational difference
I feel squeezed in the middle between antsy-verbose zoomer emailers and terse boomer emailers that hit me with ambiguous 5 word replies or those godforsaken emojii email reacts.
My decree is that 95% of emails should be three sentences double-spaced. 5% should be paragraphs. Hypertext is permissible almost entirely because of quote formatting, which should be used liberally so that each email is as self-contained as possible.
Everything is asynchronous but face-to-face, phone and video call.
I cut every communication tool settings that enable online status or "typing..." information. It sets unreasonable expectations no one should have (but in contextual requests on the spot).
written letters are asynchronous but people expected timely (relative to snail mail) replies even back then.
Chats are ambiguous because it functions both as sync and async. I treat my whatsapp messages as async, but time and again I get heat from people because I take too long to reply, something I'll never feel the urge to apologize for.