I don’t understand why potential employers think it’s appropriate to try and scold potential candidates

I had an employer reach out and scold me for not answering their phone call this morning. They said

[My Name],
It is not polite to hang up on prospective employers. You gave us your number and email because you were interested in a position.

First off I didn't hang up I was busy so I rejected the call.

Second, I'm not obligated to answer my phone to someone who is not my employer. Even if they WERE my employer I am not obligated to answer my phone for work unless I am being compensated for it.

I'm irritated now because who are you to try and scold a grown adult. So I sent this:

1. I did not hang up; I rejected the call because I was in the middle of something vital 2. It is disrespectful to assume that prospective employees wait day and night on their phones, hoping a potential employer MIGHT call and do not have other obligations 3. I do not want to work for ANYONE who assumes it is professional or appropriate to scold a grown adult because they placed a call with no notice for a POTENTIAL job that I have 0 obligations for, ESPECIALLY. After all, this action disregards that I am human and have a life and commitments. If this is how you treat potential employees, I doubt actual employees get treated with respect and dignity. Have the day you deserve.