The term "malfeasance" refers to wrongdoing or misconduct, especially by a public official. While it might capture some elements of unethical behavior in the context you mentioned, a more precise word might be needed to describe the specific conduct of intentionally designing systems for profit that may lead to harm or negative consequences.

Here are some alternatives:

1. **Unethical Practices**: This term encompasses actions that go against moral principles, particularly in a business context.

2. **Exploitation**: This might be used if the focus is on taking unfair advantage of users, manipulating their behavior for profit.

3. **Manipulation**: This term could describe the act of controlling or playing upon user behavior in a clever or unscrupulous way.

4. **Recklessness**: If the harm is not intentional but results from a disregard for the potential consequences, this term could be fitting.

5. **Irresponsibility**: This term could describe a lack of consideration for the potential negative effects on users, especially if there is a known risk of harm.

6. **Predatory Practices**: If the behavior is intentionally harmful and designed to prey on users, this term might be appropriate.

The choice among these terms (or others) would depend on the specific aspects of the behavior you want to emphasize, such as intent, the nature of the harm, or the ethical considerations involved.