I think the main takeaway is that it all comes down to expectations. If the expectation of the team and the communication medium is rapid response (minutes vs. hours/days), and that expectation is not clearly communicated and agreed upon, you're going to have trouble.

Likewise, if everyone knows that due to people's different time zones, schedules, etc. that 24hrs is a typical response window via email, there should be no complaints if responses aren't received more immediately.