Because you never, ever want to send a very private and personal message to the wrong person.
A purely (non) fictional example of this would be............
A man writes a very personal and intimate message that he intends to send to a female "friend". But instead of clicking on the name of his female friend, he accidentally clicks on the name of someone else.
Like his EX WIFE.
That would be bad.
BAD.
Not that I know anyone stupid enough to do that.
Nope.
Not me.