Why does the forum need users who cannot grow on their own, but resort to such methods? A forum's account is history, it is status, it is reputation, it is knowledge, and all this should be assigned to only one user and should not be transferred somehow.
I think part of the answer to your stance here is geography. I sympathize with some cultures in the world because let's be honest, they can make more money here on the forum than they could with a real job in their area. So, they buy accounts so they can make money to feed their families.
Most people are on this forum to make money. Whether it be btc to save for later(HODLERS), money to feed their family, money to invest to make more money, or many other reasons. Even the forum itsself made money via selling ad space in the auctions, donations, or whatever.
Now, let's get back to the people who buy accounts for sig campaigns so they can earn money to eat. Do I love the quality of the user that usually is in this situation? No, they could really learn from reading the rules and stickies and try to contribute vs spamming the forum just to be paid. They should take the time to try and be a positive aspect of the forum vs something that everyone hates.
Should we only care about the financially well off? Should we be assholes to the less fortunate? That seems to be what I notice and probably have engaged in myself at 1 time or another. Everyone that visits the forum isn't the smartest, but they could possibly be taught a better way to use the forum if we knew they were willing to learn.