What a lovely way to introduce someone new to the community...
The flip side of that statement would be 'What a lovely way to introduce yourself to the community'.
Everyone agrees to the rules when they sign up, if you did not read the rules then that is on you, not the community.
The rule exists for the safety of everyone. No one in their right mind would support the spamming of the members or scams by those who are more than willing to take advantage of others with 'drive by' offers.
So the rule gives both new members and existing members an opportunity to become familiar with each other before any transactions begin.