Don't ever second guess yourself on this, you are doing the right thing. There are multiple factors that lead to the market sustaining such a wide gap between direct and resale prices. But I believe the biggest inefficiency is lack of information. For those who were fully aware of the resale market but chose to purchase direct, that doesn't apply. But from what I understand, that is a relatively small proportion of the people who buy direct from
DVC. If people were fully aware of both purchasing markets, the gap would narrow significantly (but not entirely, because there are tangible benefits to buying direct). This would result in some type of market correction involving Disney lowering prices, resale prices increasing, Disney adding value to their offering, and/or Disney slashing value to resales without diminishing direct value. This last one is often mentioned here but is a tricky proposition, and the only one of these that further perpetuates market inefficiencies.
If you were to withhold information and steer people toward direct purchases, what you would be effectively doing is getting them to finance benefits for yourself by overpaying. There is nothing noble in that. You should be commended for shedding light on the situation and providing information so people can make informed decisions. Don't ever doubt yourself on that.