100,000% this
Buying and selling property in this fashion is against the rules. They've clarified this, and are acting accordingly. If someone gets screwed over because they broke the rules, the onus of responsibility is on them.
Should SE introduce a system that automatically scales the amount of plots available to match player demand so that anyone can buy an empty plot at list price? Yes they should, and it would evaporate the problem of housing speculation entirely (and wouldn't be that hard to code). But for whatever reason, they haven't. When we sign up to play this game, we agree to do so according to the rules they've set forth--rules that encourage fairness to other players. So if, when someone acts against the heart of those rules, they get burned, it's tough luck for them.