I disagree. If I buy an expensive piece of rental property in a city center as an investment, then the government comes in and forces me to lower my rent through some strong-arm, artificial means, they are stealing from me by keeping me from reaping the full, market-supported rewards of my investment, and theft is immoral.
You are not entitled to a return on investment. When you make an investment, you expose yourself to risks, including regulatory risks. Nothing immoral about it and certainly no theft.
In case you think we are talking hypotheticals here, what you are describing is exactly how rent control works.
